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https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 changes for 6.17, round #1
- Host driver for GICv5, the next generation interrupt controller for
arm64, including support for interrupt routing, MSIs, interrupt
translation and wired interrupts.
- Use FEAT_GCIE_LEGACY on GICv5 systems to virtualize GICv3 VMs on
GICv5 hardware, leveraging the legacy VGIC interface.
- Userspace control of the 'nASSGIcap' GICv3 feature, allowing
userspace to disable support for SGIs w/o an active state on hardware
that previously advertised it unconditionally.
- Map supporting endpoints with cacheable memory attributes on systems
with FEAT_S2FWB and DIC where KVM no longer needs to perform cache
maintenance on the address range.
- Nested support for FEAT_RAS and FEAT_DoubleFault2, allowing the guest
hypervisor to inject external aborts into an L2 VM and take traps of
masked external aborts to the hypervisor.
- Convert more system register sanitization to the config-driven
implementation.
- Fixes to the visibility of EL2 registers, namely making VGICv3 system
registers accessible through the VGIC device instead of the ONE_REG
vCPU ioctls.
- Various cleanups and minor fixes.
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KVM x86 misc changes for 6.17
- Prevert the host's DEBUGCTL.FREEZE_IN_SMM (Intel only) when running the
guest. Failure to honor FREEZE_IN_SMM can bleed host state into the guest.
- Explicitly check vmcs12.GUEST_DEBUGCTL on nested VM-Enter (Intel only) to
prevent L1 from running L2 with features that KVM doesn't support, e.g. BTF.
- Intercept SPEC_CTRL on AMD if the MSR shouldn't exist according to the
vCPU's CPUID model.
- Rework the MSR interception code so that the SVM and VMX APIs are more or
less identical.
- Recalculate all MSR intercepts from the "source" on MSR filter changes, and
drop the dedicated "shadow" bitmaps (and their awful "max" size defines).
- WARN and reject loading kvm-amd.ko instead of panicking the kernel if the
nested SVM MSRPM offsets tracker can't handle an MSR.
- Advertise support for LKGS (Load Kernel GS base), a new instruction that's
loosely related to FRED, but is supported and enumerated independently.
- Fix a user-triggerable WARN that syzkaller found by stuffing INIT_RECEIVED,
a.k.a. WFS, and then putting the vCPU into VMX Root Mode (post-VMXON). Use
the same approach KVM uses for dealing with "impossible" emulation when
running a !URG guest, and simply wait until KVM_RUN to detect that the vCPU
has architecturally impossible state.
- Add KVM_X86_DISABLE_EXITS_APERFMPERF to allow disabling interception of
APERF/MPERF reads, so that a "properly" configured VM can "virtualize"
APERF/MPERF (with many caveats).
- Reject KVM_SET_TSC_KHZ if vCPUs have been created, as changing the "default"
frequency is unsupported for VMs with a "secure" TSC, and there's no known
use case for changing the default frequency for other VM types.
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KVM/riscv changes for 6.17
- Enabled ring-based dirty memory tracking
- Improved perf kvm stat to report interrupt events
- Delegate illegal instruction trap to VS-mode
- MMU related improvements for KVM RISC-V for upcoming
nested virtualization
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Enable ring-based dirty memory tracking on riscv:
- Enable CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL as riscv is weakly
ordered.
- Set KVM_DIRTY_LOG_PAGE_OFFSET for the ring buffer's physical page
offset.
- Add a check to kvm_vcpu_kvm_riscv_check_vcpu_requests for checking
whether the dirty ring is soft full.
To handle vCPU requests that cause exits to userspace, modified the
`kvm_riscv_check_vcpu_requests` to return a value (currently only
returns 0 or 1).
Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20e116efb1f7aff211dd8e3cf8990c5521ed5f34.1749810735.git.zhouquan@iscas.ac.cn
Signed-off-by: Anup Patel <anup@brainfault.org>
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Reject KVM_SET_TSC_KHZ vCPU ioctl if guest's TSC is protected and not
changeable by KVM, and update the documentation to reflect it.
For such TSC protected guests, e.g. TDX guests, typically the TSC is
configured once at VM level before any vCPU are created and remains
unchanged during VM's lifetime. KVM provides the KVM_SET_TSC_KHZ VM
scope ioctl to allow the userspace VMM to configure the TSC of such VM.
After that the userspace VMM is not supposed to call the KVM_SET_TSC_KHZ
vCPU scope ioctl anymore when creating the vCPU.
The de facto userspace VMM Qemu does this for TDX guests. The upcoming
SEV-SNP guests with Secure TSC should follow.
Note, TDX support hasn't been fully released as of the "buggy" commit,
i.e. there is no established ABI to break.
Fixes: adafea110600 ("KVM: x86: Add infrastructure for secure TSC")
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Link: https://lore.kernel.org/r/71bbdf87fdd423e3ba3a45b57642c119ee2dd98c.1752444335.git.kai.huang@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Reject the KVM_SET_TSC_KHZ VM ioctl when vCPUs have been created and
update the documentation to reflect it.
The VM scope KVM_SET_TSC_KHZ ioctl is used to set up the default TSC
frequency that all subsequently created vCPUs can use. It is only
intended to be called before any vCPU is created. Allowing it to be
called after that only results in confusion but nothing good.
Note this is an ABI change. But currently in Qemu (the de facto
userspace VMM) only TDX uses this VM ioctl, and it is only called once
before creating any vCPU, therefore the risk of breaking userspace is
pretty low.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Link: https://lore.kernel.org/r/135a35223ce8d01cea06b6cef30bfe494ec85827.1752444335.git.kai.huang@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Add proper indentations to bullet list item to resolve the warning:
"Bullet list ends without a blank line; unexpected unindent."
Closes:https://lore.kernel.org/kvm/20250623162110.6e2f4241@canb.auug.org.au
Fixes: 4580dbef5ce0 ("KVM: TDX: Exit to userspace for SetupEventNotifyInterrupt")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Link: https://lore.kernel.org/r/20250701012536.1281367-1-binbin.wu@linux.intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Allow a guest to read the physical IA32_APERF and IA32_MPERF MSRs
without interception.
The IA32_APERF and IA32_MPERF MSRs are not virtualized. Writes are not
handled at all. The MSR values are not zeroed on vCPU creation, saved
on suspend, or restored on resume. No accommodation is made for
processor migration or for sharing a logical processor with other
tasks. No adjustments are made for non-unit TSC multipliers. The MSRs
do not account for time the same way as the comparable PMU events,
whether the PMU is virtualized by the traditional emulation method or
the new mediated pass-through approach.
Nonetheless, in a properly constrained environment, this capability
can be combined with a guest CPUID table that advertises support for
CPUID.6:ECX.APERFMPERF[bit 0] to induce a Linux guest to report the
effective physical CPU frequency in /proc/cpuinfo. Moreover, there is
no performance cost for this capability.
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20250530185239.2335185-3-jmattson@google.com
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20250626001225.744268-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Introduce a new KVM capability to expose to the userspace whether
cacheable mapping of PFNMAP is supported.
The ability to safely do the cacheable mapping of PFNMAP is contingent
on S2FWB and ARM64_HAS_CACHE_DIC. S2FWB allows KVM to avoid flushing
the D cache, ARM64_HAS_CACHE_DIC allows KVM to avoid flushing the icache
and turns icache_inval_pou() into a NOP. The cap would be false if
those requirements are missing and is checked by making use of
kvm_arch_supports_cacheable_pfnmap.
This capability would allow userspace to discover the support.
It could for instance be used by userspace to prevent live-migration
across FWB and non-FWB hosts.
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Jason Gunthorpe <jgg@nvidia.com>
CC: Oliver Upton <oliver.upton@linux.dev>
CC: David Hildenbrand <david@redhat.com>
Suggested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250705071717.5062-7-ankita@nvidia.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Add proper indentations to bullet list items to resolve the warning:
"Bullet list ends without a blank line; unexpected unindent."
Closes:https://lore.kernel.org/kvm/20250623162110.6e2f4241@canb.auug.org.au/
Fixes: cf207eac06f6 ("KVM: TDX: Handle TDG.VP.VMCALL<GetQuote>")
Fixes: 25e8b1dd4883 ("KVM: TDX: Exit to userspace for GetTdVmCallInfo")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20250625014829.82289-1-binbin.wu@linux.intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Exit to userspace for TDG.VP.VMCALL<GetTdVmCallInfo> via KVM_EXIT_TDX,
to allow userspace to provide information about the support of
TDVMCALLs when r12 is 1 for the TDVMCALLs beyond the GHCI base API.
GHCI spec defines the GHCI base TDVMCALLs: <GetTdVmCallInfo>, <MapGPA>,
<ReportFatalError>, <Instruction.CPUID>, <#VE.RequestMMIO>,
<Instruction.HLT>, <Instruction.IO>, <Instruction.RDMSR> and
<Instruction.WRMSR>. They must be supported by VMM to support TDX guests.
For GetTdVmCallInfo
- When leaf (r12) to enumerate TDVMCALL functionality is set to 0,
successful execution indicates all GHCI base TDVMCALLs listed above are
supported.
Update the KVM TDX document with the set of the GHCI base APIs.
- When leaf (r12) to enumerate TDVMCALL functionality is set to 1, it
indicates the TDX guest is querying the supported TDVMCALLs beyond
the GHCI base TDVMCALLs.
Exit to userspace to let userspace set the TDVMCALL sub-function bit(s)
accordingly to the leaf outputs. KVM could set the TDVMCALL bit(s)
supported by itself when the TDVMCALLs don't need support from userspace
after returning from userspace and before entering guest. Currently, no
such TDVMCALLs implemented, KVM just sets the values returned from
userspace.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
[Adjust userspace API. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Handle TDVMCALL for GetQuote to generate a TD-Quote.
GetQuote is a doorbell-like interface used by TDX guests to request VMM
to generate a TD-Quote signed by a service hosting TD-Quoting Enclave
operating on the host. A TDX guest passes a TD Report (TDREPORT_STRUCT) in
a shared-memory area as parameter. Host VMM can access it and queue the
operation for a service hosting TD-Quoting enclave. When completed, the
Quote is returned via the same shared-memory area.
KVM only checks the GPA from the TDX guest has the shared-bit set and drops
the shared-bit before exiting to userspace to avoid bleeding the shared-bit
into KVM's exit ABI. KVM forwards the request to userspace VMM (e.g. QEMU)
and userspace VMM queues the operation asynchronously. KVM sets the return
code according to the 'ret' field set by userspace to notify the TDX guest
whether the request has been queued successfully or not. When the request
has been queued successfully, the TDX guest can poll the status field in
the shared-memory area to check whether the Quote generation is completed
or not. When completed, the generated Quote is returned via the same
buffer.
Add KVM_EXIT_TDX as a new exit reason to userspace. Userspace is
required to handle the KVM exit reason as the initial support for TDX,
by reentering KVM to ensure that the TDVMCALL is complete. While at it,
add a note that KVM_EXIT_HYPERCALL also requires reentry with KVM_RUN.
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Tested-by: Mikko Ylinen <mikko.ylinen@linux.intel.com>
Acked-by: Kai Huang <kai.huang@intel.com>
[Adjust userspace API. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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KVM SVM changes for 6.16:
- Wait for target vCPU to acknowledge KVM_REQ_UPDATE_PROTECTED_GUEST_STATE to
fix a race between AP destroy and VMRUN.
- Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for the VM.
- Add support for ALLOWED_SEV_FEATURES.
- Add #VMGEXIT to the set of handlers special cased for CONFIG_RETPOLINE=y.
- Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing features
that utilize those bits.
- Don't account temporary allocations in sev_send_update_data().
- Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock Threshold.
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KVM/riscv changes for 6.16
- Add vector registers to get-reg-list selftest
- VCPU reset related improvements
- Remove scounteren initialization from VCPU reset
- Support VCPU reset from userspace using set_mpstate() ioctl
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git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 updates for 6.16
* New features:
- Add large stage-2 mapping support for non-protected pKVM guests,
clawing back some performance.
- Add UBSAN support to the standalone EL2 object used in nVHE/hVHE and
protected modes.
- Enable nested virtualisation support on systems that support it
(yes, it has been a long time coming), though it is disabled by
default.
* Improvements, fixes and cleanups:
- Large rework of the way KVM tracks architecture features and links
them with the effects of control bits. This ensures correctness of
emulation (the data is automatically extracted from the published
JSON files), and helps dealing with the evolution of the
architecture.
- Significant changes to the way pKVM tracks ownership of pages,
avoiding page table walks by storing the state in the hypervisor's
vmemmap. This in turn enables the THP support described above.
- New selftest checking the pKVM ownership transition rules
- Fixes for FEAT_MTE_ASYNC being accidentally advertised to guests
even if the host didn't have it.
- Fixes for the address translation emulation, which happened to be
rather buggy in some specific contexts.
- Fixes for the PMU emulation in NV contexts, decoupling PMCR_EL0.N
from the number of counters exposed to a guest and addressing a
number of issues in the process.
- Add a new selftest for the SVE host state being corrupted by a
guest.
- Keep HCR_EL2.xMO set at all times for systems running with the
kernel at EL2, ensuring that the window for interrupts is slightly
bigger, and avoiding a pretty bad erratum on the AmpereOne HW.
- Add workaround for AmpereOne's erratum AC04_CPU_23, which suffers
from a pretty bad case of TLB corruption unless accesses to HCR_EL2
are heavily synchronised.
- Add a per-VM, per-ITS debugfs entry to dump the state of the ITS
tables in a human-friendly fashion.
- and the usual random cleanups.
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Add a toggleable VM capability to reset the VCPU from userspace by
setting MP_STATE_INIT_RECEIVED through IOCTL.
Reset through a mp_state to avoid adding a new IOCTL.
Do not reset on a transition from STOPPED to RUNNABLE, because it's
better to avoid side effects that would complicate userspace adoption.
The MP_STATE_INIT_RECEIVED is not a permanent mp_state -- IOCTL resets
the VCPU while preserving the original mp_state -- because we wouldn't
gain much from having a new state it in the rest of KVM, but it's a very
non-standard use of the IOCTL.
Signed-off-by: Radim Krčmář <rkrcmar@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20250515143723.2450630-5-rkrcmar@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>
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Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM CPUs with Bus Lock
Threshold, which is close enough to VMX's Bus Lock Detection VM-Exit to
allow reusing KVM_CAP_X86_BUS_LOCK_EXIT.
The biggest difference between the two features is that Threshold is
fault-like, whereas Detection is trap-like. To allow the guest to make
forward progress, Threshold provides a per-VMCB counter which is
decremented every time a bus lock occurs, and a VM-Exit is triggered if
and only if the counter is '0'.
To provide Detection-like semantics, initialize the counter to '0', i.e.
exit on every bus lock, and when re-executing the guilty instruction, set
the counter to '1' to effectively step past the instruction.
Note, in the unlikely scenario that re-executing the instruction doesn't
trigger a bus lock, e.g. because the guest has changed memory types or
patched the guilty instruction, the bus lock counter will be left at '1',
i.e. the guest will be able to do a bus lock on a different instruction.
In a perfect world, KVM would ensure the counter is '0' if the guest has
made forward progress, e.g. if RIP has changed. But trying to close that
hole would incur non-trivial complexity, for marginal benefit; the intent
of KVM_CAP_X86_BUS_LOCK_EXIT is to allow userspace rate-limit bus locks,
not to allow for precise detection of problematic guest code. And, it's
simply not feasible to fully close the hole, e.g. if an interrupt arrives
before the original instruction can re-execute, the guest could step past
a different bus lock.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Manali Shukla <manali.shukla@amd.com>
Link: https://lore.kernel.org/r/20250502050346.14274-5-manali.shukla@amd.com
[sean: fix typo in comment]
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Describe the two new vcpu flags that control NV, together with
the capabilities that advertise them.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20250514103501.2225951-18-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
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This large commit contains the initial support for TDX in KVM. All x86
parts enable the host-side hypercalls that KVM uses to talk to the TDX
module, a software component that runs in a special CPU mode called SEAM
(Secure Arbitration Mode).
The series is in turn split into multiple sub-series, each with a separate
merge commit:
- Initialization: basic setup for using the TDX module from KVM, plus
ioctls to create TDX VMs and vCPUs.
- MMU: in TDX, private and shared halves of the address space are mapped by
different EPT roots, and the private half is managed by the TDX module.
Using the support that was added to the generic MMU code in 6.14,
add support for TDX's secure page tables to the Intel side of KVM.
Generic KVM code takes care of maintaining a mirror of the secure page
tables so that they can be queried efficiently, and ensuring that changes
are applied to both the mirror and the secure EPT.
- vCPU enter/exit: implement the callbacks that handle the entry of a TDX
vCPU (via the SEAMCALL TDH.VP.ENTER) and the corresponding save/restore
of host state.
- Userspace exits: introduce support for guest TDVMCALLs that KVM forwards to
userspace. These correspond to the usual KVM_EXIT_* "heavyweight vmexits"
but are triggered through a different mechanism, similar to VMGEXIT for
SEV-ES and SEV-SNP.
- Interrupt handling: support for virtual interrupt injection as well as
handling VM-Exits that are caused by vectored events. Exclusive to
TDX are machine-check SMIs, which the kernel already knows how to
handle through the kernel machine check handler (commit 7911f145de5f,
"x86/mce: Implement recovery for errors in TDX/SEAM non-root mode")
- Loose ends: handling of the remaining exits from the TDX module, including
EPT violation/misconfig and several TDVMCALL leaves that are handled in
the kernel (CPUID, HLT, RDMSR/WRMSR, GetTdVmCallInfo); plus returning
an error or ignoring operations that are not supported by TDX guests
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Trap and emulate virtualization is not available anymore for MIPS.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Categorize the capabilities correctly. Section 6 is for enabled vCPU
capabilities; section 7 is for enabled VM capabilities; section 8 is
for informational ones.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Ensure that they have a ":" in front of the defined item.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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It is redundant, and sometimes wrong.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The capability is incorrectly called KVM_CAP_PPC_MULTITCE in the documentation.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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TSC_DEADLINE is now advertised unconditionally by KVM_GET_SUPPORTED_CPUID,
since commit 9be4ec35d668 ("KVM: x86: Advertise TSC_DEADLINE_TIMER in
KVM_GET_SUPPORTED_CPUID", 2024-12-18). Adjust the documentation to
reflect the new behavior.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20250331150550.510320-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 updates for 6.15
- Nested virtualization support for VGICv3, giving the nested
hypervisor control of the VGIC hardware when running an L2 VM
- Removal of 'late' nested virtualization feature register masking,
making the supported feature set directly visible to userspace
- Support for emulating FEAT_PMUv3 on Apple silicon, taking advantage
of an IMPLEMENTATION DEFINED trap that covers all PMUv3 registers
- Paravirtual interface for discovering the set of CPU implementations
where a VM may run, addressing a longstanding issue of guest CPU
errata awareness in big-little systems and cross-implementation VM
migration
- Userspace control of the registers responsible for identifying a
particular CPU implementation (MIDR_EL1, REVIDR_EL1, AIDR_EL1),
allowing VMs to be migrated cross-implementation
- pKVM updates, including support for tracking stage-2 page table
allocations in the protected hypervisor in the 'SecPageTable' stat
- Fixes to vPMU, ensuring that userspace updates to the vPMU after
KVM_RUN are reflected into the backing perf events
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Add documentation to Intel Trusted Domain Extensions (TDX) support.
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Message-ID: <20250227012021.1778144-21-binbin.wu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Introduce an Intel specific quirk KVM_X86_QUIRK_IGNORE_GUEST_PAT to have
KVM ignore guest PAT when this quirk is enabled.
On AMD platforms, KVM always honors guest PAT. On Intel however there are
two issues. First, KVM *cannot* honor guest PAT if CPU feature self-snoop
is not supported. Second, UC access on certain Intel platforms can be very
slow[1] and honoring guest PAT on those platforms may break some old
guests that accidentally specify video RAM as UC. Those old guests may
never expect the slowness since KVM always forces WB previously. See [2].
So, introduce a quirk that KVM can enable by default on all Intel platforms
to avoid breaking old unmodifiable guests. Newer userspace can disable this
quirk if it wishes KVM to honor guest PAT; disabling the quirk will fail
if self-snoop is not supported, i.e. if KVM cannot obey the wish.
The quirk is a no-op on AMD and also if any assigned devices have
non-coherent DMA. This is not an issue, as KVM_X86_QUIRK_CD_NW_CLEARED is
another example of a quirk that is sometimes automatically disabled.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Link: https://lore.kernel.org/all/Ztl9NWCOupNfVaCA@yzhao56-desk.sh.intel.com # [1]
Link: https://lore.kernel.org/all/87jzfutmfc.fsf@redhat.com # [2]
Message-ID: <20250224070946.31482-1-yan.y.zhao@intel.com>
[Use supported_quirks/inapplicable_quirks to support both AMD and
no-self-snoop cases, as well as to remove the shadow_memtype_mask check
from kvm_mmu_may_ignore_guest_pat(). - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Convert TDG.VP.VMCALL<ReportFatalError> to KVM_EXIT_SYSTEM_EVENT with
a new type KVM_SYSTEM_EVENT_TDX_FATAL and forward it to userspace for
handling.
TD guest can use TDG.VP.VMCALL<ReportFatalError> to report the fatal
error it has experienced. This hypercall is special because TD guest
is requesting a termination with the error information, KVM needs to
forward the hypercall to userspace anyway, KVM doesn't do parsing or
conversion, it just dumps the 16 general-purpose registers to userspace
and let userspace decide what to do.
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Message-ID: <20250222014225.897298-8-binbin.wu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The capability actually fails with EINVAL if vCPUs have already been
created.
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305230825.484091-4-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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KVM's treatment of the ID registers that describe the implementation
(MIDR, REVIDR, and AIDR) is interesting, to say the least. On the
userspace-facing end of it, KVM presents the values of the boot CPU on
all vCPUs and treats them as invariant. On the guest side of things KVM
presents the hardware values of the local CPU, which can change during
CPU migration in a big-little system.
While one may call this fragile, there is at least some degree of
predictability around it. For example, if a VMM wanted to present
big-little to a guest, it could affine vCPUs accordingly to the correct
clusters.
All of this makes a giant mess out of adding support for making these
implementation ID registers writable. Avoid breaking the rather subtle
ABI around the old way of doing things by requiring opt-in from
userspace to make the registers writable.
When the cap is enabled, allow userspace to set MIDR, REVIDR, and AIDR
to any non-reserved value and present those values consistently across
all vCPUs.
Signed-off-by: Sebastian Ott <sebott@redhat.com>
[oliver: changelog, capability]
Link: https://lore.kernel.org/r/20250225005401.679536-5-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Reject userspace attempts to set the Xen hypercall page MSR to an index
outside of the "standard" virtualization range [0x40000000, 0x4fffffff],
as KVM is not equipped to handle collisions with real MSRs, e.g. KVM
doesn't update MSR interception, conflicts with VMCS/VMCB fields, special
case writes in KVM, etc.
While the MSR index isn't strictly ABI, i.e. can theoretically float to
any value, in practice no known VMM sets the MSR index to anything other
than 0x40000000 or 0x40000200.
Cc: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Link: https://lore.kernel.org/r/20250215011437.1203084-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Create a fake memslot for ucontrol VMs. The fake memslot identity-maps
userspace.
Now memslots will always be present, and ucontrol is not a special case
anymore.
Suggested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20250123144627.312456-4-imbrenda@linux.ibm.com
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20250123144627.312456-4-imbrenda@linux.ibm.com>
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Pull kvm updates from Paolo Bonzini:
"Loongarch:
- Clear LLBCTL if secondary mmu mapping changes
- Add hypercall service support for usermode VMM
x86:
- Add a comment to kvm_mmu_do_page_fault() to explain why KVM
performs a direct call to kvm_tdp_page_fault() when RETPOLINE is
enabled
- Ensure that all SEV code is compiled out when disabled in Kconfig,
even if building with less brilliant compilers
- Remove a redundant TLB flush on AMD processors when guest CR4.PGE
changes
- Use str_enabled_disabled() to replace open coded strings
- Drop kvm_x86_ops.hwapic_irr_update() as KVM updates hardware's
APICv cache prior to every VM-Enter
- Overhaul KVM's CPUID feature infrastructure to track all vCPU
capabilities instead of just those where KVM needs to manage state
and/or explicitly enable the feature in hardware. Along the way,
refactor the code to make it easier to add features, and to make it
more self-documenting how KVM is handling each feature
- Rework KVM's handling of VM-Exits during event vectoring; this
plugs holes where KVM unintentionally puts the vCPU into infinite
loops in some scenarios (e.g. if emulation is triggered by the
exit), and brings parity between VMX and SVM
- Add pending request and interrupt injection information to the
kvm_exit and kvm_entry tracepoints respectively
- Fix a relatively benign flaw where KVM would end up redoing RDPKRU
when loading guest/host PKRU, due to a refactoring of the kernel
helpers that didn't account for KVM's pre-checking of the need to
do WRPKRU
- Make the completion of hypercalls go through the complete_hypercall
function pointer argument, no matter if the hypercall exits to
userspace or not.
Previously, the code assumed that KVM_HC_MAP_GPA_RANGE specifically
went to userspace, and all the others did not; the new code need
not special case KVM_HC_MAP_GPA_RANGE and in fact does not care at
all whether there was an exit to userspace or not
- As part of enabling TDX virtual machines, support support
separation of private/shared EPT into separate roots.
When TDX will be enabled, operations on private pages will need to
go through the privileged TDX Module via SEAMCALLs; as a result,
they are limited and relatively slow compared to reading a PTE.
The patches included in 6.14 allow KVM to keep a mirror of the
private EPT in host memory, and define entries in kvm_x86_ops to
operate on external page tables such as the TDX private EPT
- The recently introduced conversion of the NX-page reclamation
kthread to vhost_task moved the task under the main process. The
task is created as soon as KVM_CREATE_VM was invoked and this, of
course, broke userspace that didn't expect to see any child task of
the VM process until it started creating its own userspace threads.
In particular crosvm refuses to fork() if procfs shows any child
task, so unbreak it by creating the task lazily. This is arguably a
userspace bug, as there can be other kinds of legitimate worker
tasks and they wouldn't impede fork(); but it's not like userspace
has a way to distinguish kernel worker tasks right now. Should they
show as "Kthread: 1" in proc/.../status?
x86 - Intel:
- Fix a bug where KVM updates hardware's APICv cache of the highest
ISR bit while L2 is active, while ultimately results in a
hardware-accelerated L1 EOI effectively being lost
- Honor event priority when emulating Posted Interrupt delivery
during nested VM-Enter by queueing KVM_REQ_EVENT instead of
immediately handling the interrupt
- Rework KVM's processing of the Page-Modification Logging buffer to
reap entries in the same order they were created, i.e. to mark gfns
dirty in the same order that hardware marked the page/PTE dirty
- Misc cleanups
Generic:
- Cleanup and harden kvm_set_memory_region(); add proper lockdep
assertions when setting memory regions and add a dedicated API for
setting KVM-internal memory regions. The API can then explicitly
disallow all flags for KVM-internal memory regions
- Explicitly verify the target vCPU is online in kvm_get_vcpu() to
fix a bug where KVM would return a pointer to a vCPU prior to it
being fully online, and give kvm_for_each_vcpu() similar treatment
to fix a similar flaw
- Wait for a vCPU to come online prior to executing a vCPU ioctl, to
fix a bug where userspace could coerce KVM into handling the ioctl
on a vCPU that isn't yet onlined
- Gracefully handle xarray insertion failures; even though such
failures are impossible in practice after xa_reserve(), reserving
an entry is always followed by xa_store() which does not know (or
differentiate) whether there was an xa_reserve() before or not
RISC-V:
- Zabha, Svvptc, and Ziccrse extension support for guests. None of
them require anything in KVM except for detecting them and marking
them as supported; Zabha adds byte and halfword atomic operations,
while the others are markers for specific operation of the TLB and
of LL/SC instructions respectively
- Virtualize SBI system suspend extension for Guest/VM
- Support firmware counters which can be used by the guests to
collect statistics about traps that occur in the host
Selftests:
- Rework vcpu_get_reg() to return a value instead of using an
out-param, and update all affected arch code accordingly
- Convert the max_guest_memory_test into a more generic
mmu_stress_test. The basic gist of the "conversion" is to have the
test do mprotect() on guest memory while vCPUs are accessing said
memory, e.g. to verify KVM and mmu_notifiers are working as
intended
- Play nice with treewrite builds of unsupported architectures, e.g.
arm (32-bit), as KVM selftests' Makefile doesn't do anything to
ensure the target architecture is actually one KVM selftests
supports
- Use the kernel's $(ARCH) definition instead of the target triple
for arch specific directories, e.g. arm64 instead of aarch64,
mainly so as not to be different from the rest of the kernel
- Ensure that format strings for logging statements are checked by
the compiler even when the logging statement itself is disabled
- Attempt to whack the last LLC references/misses mole in the Intel
PMU counters test by adding a data load and doing CLFLUSH{OPT} on
the data instead of the code being executed. It seems that modern
Intel CPUs have learned new code prefetching tricks that bypass the
PMU counters
- Fix a flaw in the Intel PMU counters test where it asserts that
events are counting correctly without actually knowing what the
events count given the underlying hardware; this can happen if
Intel reuses a formerly microarchitecture-specific event encoding
as an architectural event, as was the case for Top-Down Slots"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (151 commits)
kvm: defer huge page recovery vhost task to later
KVM: x86/mmu: Return RET_PF* instead of 1 in kvm_mmu_page_fault()
KVM: Disallow all flags for KVM-internal memslots
KVM: x86: Drop double-underscores from __kvm_set_memory_region()
KVM: Add a dedicated API for setting KVM-internal memslots
KVM: Assert slots_lock is held when setting memory regions
KVM: Open code kvm_set_memory_region() into its sole caller (ioctl() API)
LoongArch: KVM: Add hypercall service support for usermode VMM
LoongArch: KVM: Clear LLBCTL if secondary mmu mapping is changed
KVM: SVM: Use str_enabled_disabled() helper in svm_hardware_setup()
KVM: VMX: read the PML log in the same order as it was written
KVM: VMX: refactor PML terminology
KVM: VMX: Fix comment of handle_vmx_instruction()
KVM: VMX: Reinstate __exit attribute for vmx_exit()
KVM: SVM: Use str_enabled_disabled() helper in sev_hardware_setup()
KVM: x86: Avoid double RDPKRU when loading host/guest PKRU
KVM: x86: Use LVT_TIMER instead of an open coded literal
RISC-V: KVM: Add new exit statstics for redirected traps
RISC-V: KVM: Update firmware counters for various events
RISC-V: KVM: Redirect instruction access fault trap to guest
...
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Pull Documentation updates from Jonathan Corbet:
- Quite a bit of Chinese and Spanish translation work
- Clarifying that Git commit IDs >12chars are OK
- A new nvme-multipath document
- A reorganization of the admin-guide top-level page to make it
readable
- Clarification of the role of Acked-by and maintainer discretion on
their acceptance
- Some reorganization of debugging-oriented docs
... and typo fixes, documentation updates, etc as usual
* tag 'docs-6.14' of git://git.lwn.net/linux: (50 commits)
Documentation: Fix x86_64 UEFI outdated references to elilo
Documentation/sysctl: Add timer_migration to kernel.rst
docs/mm: Physical memory: Remove zone_t
docs: submitting-patches: clarify that signers may use their discretion on tags
docs: submitting-patches: clarify difference between Acked-by and Reviewed-by
docs: submitting-patches: clarify Acked-by and introduce "# Suffix"
Documentation: bug-hunting.rst: remove odd contact information
docs/zh_CN: Add sak index Chinese translation
doc: module: DEFAULT_SYMBOL_NAMESPACE must be defined before #includes
doc: module: Fix documented type of namespace
Documentation/kernel-parameters: Fix a reference to vga-softcursor.rst
docs/zh_CN: Add landlock index Chinese translation
Documentation: Fix typo localmodonfig -> localmodconfig
overlayfs.rst: Fix and improve grammar
docs/zh_CN: Add siphash index Chinese translation
docs/zh_CN: Add security IMA-templates Chinese translation
docs/zh_CN: Add security digsig Chinese translation
Align git commit ID abbreviation guidelines and checks
docs: process: submitting-patches: split canonical patch format section
docs/zh_CN: Add security lsm Chinese translation
...
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KVM x86 misc changes for 6.14:
- Overhaul KVM's CPUID feature infrastructure to track all vCPU capabilities
instead of just those where KVM needs to manage state and/or explicitly
enable the feature in hardware. Along the way, refactor the code to make
it easier to add features, and to make it more self-documenting how KVM
is handling each feature.
- Rework KVM's handling of VM-Exits during event vectoring; this plugs holes
where KVM unintentionally puts the vCPU into infinite loops in some scenarios
(e.g. if emulation is triggered by the exit), and brings parity between VMX
and SVM.
- Add pending request and interrupt injection information to the kvm_exit and
kvm_entry tracepoints respectively.
- Fix a relatively benign flaw where KVM would end up redoing RDPKRU when
loading guest/host PKRU, due to a refactoring of the kernel helpers that
didn't account for KVM's pre-checking of the need to do WRPKRU.
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Prevent null pointer dereference when processing
KVM_IRQ_ROUTING_S390_ADAPTER routing entries.
The ioctl cannot be processed for ucontrol VMs.
Fixes: f65470661f36 ("KVM: s390/interrupt: do not pin adapter interrupt pages")
Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Tested-by: Hariharan Mari <hari55@linux.ibm.com>
Reviewed-by: Hariharan Mari <hari55@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20241216092140.329196-4-schlameuss@linux.ibm.com
Message-ID: <20241216092140.329196-4-schlameuss@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Unconditionally advertise TSC_DEADLINE_TIMER via KVM_GET_SUPPORTED_CPUID,
as KVM always emulates deadline mode, *if* the VM has an in-kernel local
APIC. The odds of a VMM emulating the local APIC in userspace, not
emulating the TSC deadline timer, _and_ reflecting
KVM_GET_SUPPORTED_CPUID back into KVM_SET_CPUID2, i.e. the risk of
over-advertising and breaking any setups, is extremely low.
KVM has _unconditionally_ advertised X2APIC via CPUID since commit
0d1de2d901f4 ("KVM: Always report x2apic as supported feature"), and it
is completely impossible for userspace to emulate X2APIC as KVM doesn't
support forwarding the MSR accesses to userspace. I.e. KVM has relied on
userspace VMMs to not misreport local APIC capabilities for nearly 13
years.
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20241128013424.4096668-38-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Reject KVM_CAP_X86_DISABLE_EXITS if vCPUs have been created, as disabling
PAUSE/MWAIT/HLT exits after vCPUs have been created is broken and useless,
e.g. except for PAUSE on SVM, the relevant intercepts aren't updated after
vCPU creation. vCPUs may also end up with an inconsistent configuration
if exits are disabled between creation of multiple vCPUs.
Cc: Hou Wenlong <houwenlong.hwl@antgroup.com>
Link: https://lore.kernel.org/all/9227068821b275ac547eb2ede09ec65d2281fe07.1680179693.git.houwenlong.hwl@antgroup.com
Link: https://lore.kernel.org/all/20230121020738.2973-2-kechenl@nvidia.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Link: https://lore.kernel.org/r/20241128013424.4096668-14-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Fix minor typo in api.rst where the word physical was misspelled
as physcial.
Signed-off-by: Gianfranco Trad <gianf.trad@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241115011831.300705-5-gianf.trad@gmail.com
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https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 changes for 6.13, part #1
- Support for stage-1 permission indirection (FEAT_S1PIE) and
permission overlays (FEAT_S1POE), including nested virt + the
emulated page table walker
- Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This call
was introduced in PSCIv1.3 as a mechanism to request hibernation,
similar to the S4 state in ACPI
- Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
part of it, introduce trivial initialization of the host's MPAM
context so KVM can use the corresponding traps
- PMU support under nested virtualization, honoring the guest
hypervisor's trap configuration and event filtering when running a
nested guest
- Fixes to vgic ITS serialization where stale device/interrupt table
entries are not zeroed when the mapping is invalidated by the VM
- Avoid emulated MMIO completion if userspace has requested synchronous
external abort injection
- Various fixes and cleanups affecting pKVM, vCPU initialization, and
selftests
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- Drop obsolete references to PPC970 KVM, which was removed 10 years ago.
- Fix incorrect references to non-existing ioctls
- List registers supported by KVM_GET/SET_ONE_REG on s390
- Use rST internal links
- Reorganize the introduction to the API document
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* kvm-arm64/psci-1.3:
: PSCI v1.3 support, courtesy of David Woodhouse
:
: Bump KVM's PSCI implementation up to v1.3, with the added bonus of
: implementing the SYSTEM_OFF2 call. Like other system-scoped PSCI calls,
: this gets relayed to userspace for further processing with a new
: KVM_SYSTEM_EVENT_SHUTDOWN flag.
:
: As an added bonus, implement client-side support for hibernation with
: the SYSTEM_OFF2 call.
arm64: Use SYSTEM_OFF2 PSCI call to power off for hibernate
KVM: arm64: nvhe: Pass through PSCI v1.3 SYSTEM_OFF2 call
KVM: selftests: Add test for PSCI SYSTEM_OFF2
KVM: arm64: Add support for PSCI v1.2 and v1.3
KVM: arm64: Add PSCI v1.3 SYSTEM_OFF2 function for hibernation
firmware/psci: Add definitions for PSCI v1.3 specification
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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Reorganize the text to mention file descriptors as early as possible.
Also mention capabilities early as they are a central part of KVM's
API.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241023124507.280382-5-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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In order to simplify further introduction of hyperlinks, replace explicit
section numbers with rST hyperlinks. The section numbers could actually
be removed now, but I'm not going to do a huge change throughout the file
for an RFC...
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241023124507.280382-4-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The only occurrence "Capability: none" actually meant the same as "basic".
Fix that and a few more aesthetic or content issues in the document.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241023124507.280382-3-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This was only needed for PPC970 support, which is long gone: the
implementation was removed in 2014.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241023124507.280382-2-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add a quirk to control KVM's misguided initialization of select feature
MSRs to KVM's max configuration, as enabling features by default violates
KVM's approach of letting userspace own the vCPU model, and is actively
problematic for MSRs that are conditionally supported, as the vCPU will
end up with an MSR value that userspace can't restore. E.g. if the vCPU
is configured with PDCM=0, userspace will save and attempt to restore a
non-zero PERF_CAPABILITIES, thanks to KVM's meddling.
Link: https://lore.kernel.org/r/20240802185511.305849-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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The PSCI v1.3 specification adds support for a SYSTEM_OFF2 function
which is analogous to ACPI S4 state. This will allow hosting
environments to determine that a guest is hibernated rather than just
powered off, and ensure that they preserve the virtual environment
appropriately to allow the guest to resume safely (or bump the
hardware_signature in the FACS to trigger a clean reboot instead).
This feature is safe to enable unconditionally (in a subsequent commit)
because it is exposed to userspace through the existing
KVM_SYSTEM_EVENT_SHUTDOWN event, just with an additional flag which
userspace can use to know that the instance intended hibernation instead
of a plain power-off.
As with SYSTEM_RESET2, there is only one type available (in this case
HIBERNATE_OFF), and it is not explicitly reported to userspace through
the event; userspace can get it from the registers if it cares).
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Miguel Luis <miguel.luis@oracle.com>
Link: https://lore.kernel.org/r/20241019172459.2241939-3-dwmw2@infradead.org
[oliver: slight cleanup of comments]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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