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2022-12-29KVM: Drop kvm_arch_check_processor_compat() hookSean Christopherson
Drop kvm_arch_check_processor_compat() and its support code now that all architecture implementations are nops. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390 Acked-by: Anup Patel <anup@brainfault.org> Reviewed-by: Kai Huang <kai.huang@intel.com> Message-Id: <20221130230934.1014142-33-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-29KVM: x86: Do CPU compatibility checks in x86 codeSean Christopherson
Move the CPU compatibility checks to pure x86 code, i.e. drop x86's use of the common kvm_x86_check_cpu_compat() arch hook. x86 is the only architecture that "needs" to do per-CPU compatibility checks, moving the logic to x86 will allow dropping the common code, and will also give x86 more control over when/how the compatibility checks are performed, e.g. TDX will need to enable hardware (do VMXON) in order to perform compatibility checks. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com> Reviewed-by: Kai Huang <kai.huang@intel.com> Message-Id: <20221130230934.1014142-32-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-29KVM: x86: Move guts of kvm_arch_init() to standalone helperSean Christopherson
Move the guts of kvm_arch_init() to a new helper, kvm_x86_vendor_init(), so that VMX can do _all_ arch and vendor initialization before calling kvm_init(). Calling kvm_init() must be the _very_ last step during init, as kvm_init() exposes /dev/kvm to userspace, i.e. allows creating VMs. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-14-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-12-15Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm updates from Paolo Bonzini: "ARM64: - Enable the per-vcpu dirty-ring tracking mechanism, together with an option to keep the good old dirty log around for pages that are dirtied by something other than a vcpu. - Switch to the relaxed parallel fault handling, using RCU to delay page table reclaim and giving better performance under load. - Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping option, which multi-process VMMs such as crosvm rely on (see merge commit 382b5b87a97d: "Fix a number of issues with MTE, such as races on the tags being initialised vs the PG_mte_tagged flag as well as the lack of support for VM_SHARED when KVM is involved. Patches from Catalin Marinas and Peter Collingbourne"). - Merge the pKVM shadow vcpu state tracking that allows the hypervisor to have its own view of a vcpu, keeping that state private. - Add support for the PMUv3p5 architecture revision, bringing support for 64bit counters on systems that support it, and fix the no-quite-compliant CHAIN-ed counter support for the machines that actually exist out there. - Fix a handful of minor issues around 52bit VA/PA support (64kB pages only) as a prefix of the oncoming support for 4kB and 16kB pages. - Pick a small set of documentation and spelling fixes, because no good merge window would be complete without those. s390: - Second batch of the lazy destroy patches - First batch of KVM changes for kernel virtual != physical address support - Removal of a unused function x86: - Allow compiling out SMM support - Cleanup and documentation of SMM state save area format - Preserve interrupt shadow in SMM state save area - Respond to generic signals during slow page faults - Fixes and optimizations for the non-executable huge page errata fix. - Reprogram all performance counters on PMU filter change - Cleanups to Hyper-V emulation and tests - Process Hyper-V TLB flushes from a nested guest (i.e. from a L2 guest running on top of a L1 Hyper-V hypervisor) - Advertise several new Intel features - x86 Xen-for-KVM: - Allow the Xen runstate information to cross a page boundary - Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured - Add support for 32-bit guests in SCHEDOP_poll - Notable x86 fixes and cleanups: - One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0). - Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few years back when eliminating unnecessary barriers when switching between vmcs01 and vmcs02. - Clean up vmread_error_trampoline() to make it more obvious that params must be passed on the stack, even for x86-64. - Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective of the current guest CPUID. - Fudge around a race with TSC refinement that results in KVM incorrectly thinking a guest needs TSC scaling when running on a CPU with a constant TSC, but no hardware-enumerated TSC frequency. - Advertise (on AMD) that the SMM_CTL MSR is not supported - Remove unnecessary exports Generic: - Support for responding to signals during page faults; introduces new FOLL_INTERRUPTIBLE flag that was reviewed by mm folks Selftests: - Fix an inverted check in the access tracking perf test, and restore support for asserting that there aren't too many idle pages when running on bare metal. - Fix build errors that occur in certain setups (unsure exactly what is unique about the problematic setup) due to glibc overriding static_assert() to a variant that requires a custom message. - Introduce actual atomics for clear/set_bit() in selftests - Add support for pinning vCPUs in dirty_log_perf_test. - Rename the so called "perf_util" framework to "memstress". - Add a lightweight psuedo RNG for guest use, and use it to randomize the access pattern and write vs. read percentage in the memstress tests. - Add a common ucall implementation; code dedup and pre-work for running SEV (and beyond) guests in selftests. - Provide a common constructor and arch hook, which will eventually be used by x86 to automatically select the right hypercall (AMD vs. Intel). - A bunch of added/enabled/fixed selftests for ARM64, covering memslots, breakpoints, stage-2 faults and access tracking. - x86-specific selftest changes: - Clean up x86's page table management. - Clean up and enhance the "smaller maxphyaddr" test, and add a related test to cover generic emulation failure. - Clean up the nEPT support checks. - Add X86_PROPERTY_* framework to retrieve multi-bit CPUID values. - Fix an ordering issue in the AMX test introduced by recent conversions to use kvm_cpu_has(), and harden the code to guard against similar bugs in the future. Anything that tiggers caching of KVM's supported CPUID, kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if the caching occurs before the test opts in via prctl(). Documentation: - Remove deleted ioctls from documentation - Clean up the docs for the x86 MSR filter. - Various fixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (361 commits) KVM: x86: Add proper ReST tables for userspace MSR exits/flags KVM: selftests: Allocate ucall pool from MEM_REGION_DATA KVM: arm64: selftests: Align VA space allocator with TTBR0 KVM: arm64: Fix benign bug with incorrect use of VA_BITS KVM: arm64: PMU: Fix period computation for 64bit counters with 32bit overflow KVM: x86: Advertise that the SMM_CTL MSR is not supported KVM: x86: remove unnecessary exports KVM: selftests: Fix spelling mistake "probabalistic" -> "probabilistic" tools: KVM: selftests: Convert clear/set_bit() to actual atomics tools: Drop "atomic_" prefix from atomic test_and_set_bit() tools: Drop conflicting non-atomic test_and_{clear,set}_bit() helpers KVM: selftests: Use non-atomic clear/set bit helpers in KVM tests perf tools: Use dedicated non-atomic clear/set bit helpers tools: Take @bit as an "unsigned long" in {clear,set}_bit() helpers KVM: arm64: selftests: Enable single-step without a "full" ucall() KVM: x86: fix APICv/x2AVIC disabled when vm reboot by itself KVM: Remove stale comment about KVM_REQ_UNHALT KVM: Add missing arch for KVM_CREATE_DEVICE and KVM_{SET,GET}_DEVICE_ATTR KVM: Reference to kvm_userspace_memory_region in doc and comments KVM: Delete all references to removed KVM_SET_MEMORY_ALIAS ioctl ...
2022-11-30KVM: SVM: Skip WRMSR fastpath on VM-Exit if next RIP isn't validSean Christopherson
Skip the WRMSR fastpath in SVM's VM-Exit handler if the next RIP isn't valid, e.g. because KVM is running with nrips=false. SVM must decode and emulate to skip the WRMSR if the CPU doesn't provide the next RIP. Getting the instruction bytes to decode the WRMSR requires reading guest memory, which in turn means dereferencing memslots, and that isn't safe because KVM doesn't hold SRCU when the fastpath runs. Don't bother trying to enable the fastpath for this case, e.g. by doing only the WRMSR and leaving the "skip" until later. NRIPS is supported on all modern CPUs (KVM has considered making it mandatory), and the next RIP will be valid the vast, vast majority of the time. ============================= WARNING: suspicious RCU usage 6.0.0-smp--4e557fcd3d80-skip #13 Tainted: G O ----------------------------- include/linux/kvm_host.h:954 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by stable/206475: #0: ffff9d9dfebcc0f0 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x8b/0x620 [kvm] stack backtrace: CPU: 152 PID: 206475 Comm: stable Tainted: G O 6.0.0-smp--4e557fcd3d80-skip #13 Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 10.48.0 01/27/2022 Call Trace: <TASK> dump_stack_lvl+0x69/0xaa dump_stack+0x10/0x12 lockdep_rcu_suspicious+0x11e/0x130 kvm_vcpu_gfn_to_memslot+0x155/0x190 [kvm] kvm_vcpu_gfn_to_hva_prot+0x18/0x80 [kvm] paging64_walk_addr_generic+0x183/0x450 [kvm] paging64_gva_to_gpa+0x63/0xd0 [kvm] kvm_fetch_guest_virt+0x53/0xc0 [kvm] __do_insn_fetch_bytes+0x18b/0x1c0 [kvm] x86_decode_insn+0xf0/0xef0 [kvm] x86_emulate_instruction+0xba/0x790 [kvm] kvm_emulate_instruction+0x17/0x20 [kvm] __svm_skip_emulated_instruction+0x85/0x100 [kvm_amd] svm_skip_emulated_instruction+0x13/0x20 [kvm_amd] handle_fastpath_set_msr_irqoff+0xae/0x180 [kvm] svm_vcpu_run+0x4b8/0x5a0 [kvm_amd] vcpu_enter_guest+0x16ca/0x22f0 [kvm] kvm_arch_vcpu_ioctl_run+0x39d/0x900 [kvm] kvm_vcpu_ioctl+0x538/0x620 [kvm] __se_sys_ioctl+0x77/0xc0 __x64_sys_ioctl+0x1d/0x20 do_syscall_64+0x3d/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: 404d5d7bff0d ("KVM: X86: Introduce more exit_fastpath_completion enum values") Signed-off-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20220930234031.1732249-1-seanjc@google.com
2022-11-27Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm fixes from Paolo Bonzini: "x86: - Fixes for Xen emulation. While nobody should be enabling it in the kernel (the only public users of the feature are the selftests), the bug effectively allows userspace to read arbitrary memory. - Correctness fixes for nested hypervisors that do not intercept INIT or SHUTDOWN on AMD; the subsequent CPU reset can cause a use-after-free when it disables virtualization extensions. While downgrading the panic to a WARN is quite easy, the full fix is a bit more laborious; there are also tests. This is the bulk of the pull request. - Fix race condition due to incorrect mmu_lock use around make_mmu_pages_available(). Generic: - Obey changes to the kvm.halt_poll_ns module parameter in VMs not using KVM_CAP_HALT_POLL, restoring behavior from before the introduction of the capability" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: Update gfn_to_pfn_cache khva when it moves within the same page KVM: x86/xen: Only do in-kernel acceleration of hypercalls for guest CPL0 KVM: x86/xen: Validate port number in SCHEDOP_poll KVM: x86/mmu: Fix race condition in direct_page_fault KVM: x86: remove exit_int_info warning in svm_handle_exit KVM: selftests: add svm part to triple_fault_test KVM: x86: allow L1 to not intercept triple fault kvm: selftests: add svm nested shutdown test KVM: selftests: move idt_entry to header KVM: x86: forcibly leave nested mode on vCPU reset KVM: x86: add kvm_leave_nested KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while still in use KVM: x86: nSVM: leave nested mode on vCPU free KVM: Obey kvm.halt_poll_ns in VMs not using KVM_CAP_HALT_POLL KVM: Avoid re-reading kvm->max_halt_poll_ns during halt-polling KVM: Cap vcpu->halt_poll_ns before halting rather than after
2022-11-18KVM: x86: hyper-v: Introduce TLB flush fifoVitaly Kuznetsov
To allow flushing individual GVAs instead of always flushing the whole VPID a per-vCPU structure to pass the requests is needed. Use standard 'kfifo' to queue two types of entries: individual GVA (GFN + up to 4095 following GFNs in the lower 12 bits) and 'flush all'. The size of the fifo is arbitrarily set to '16'. Note, kvm_hv_flush_tlb() only queues 'flush all' entries for now and kvm_hv_vcpu_flush_tlb() doesn't actually read the fifo just resets the queue before returning -EOPNOTSUPP (which triggers full TLB flush) so the functional change is very small but the infrastructure is prepared to handle individual GVA flush requests. Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20221101145426.251680-10-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-18KVM: x86: hyper-v: Resurrect dedicated KVM_REQ_HV_TLB_FLUSH flagVitaly Kuznetsov
In preparation to implementing fine-grained Hyper-V TLB flush and L2 TLB flush, resurrect dedicated KVM_REQ_HV_TLB_FLUSH request bit. As KVM_REQ_TLB_FLUSH_GUEST is a stronger operation, clear KVM_REQ_HV_TLB_FLUSH request in kvm_vcpu_flush_tlb_guest(). The flush itself is temporary handled by kvm_vcpu_flush_tlb_guest(). No functional change intended. Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20221101145426.251680-9-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-17Merge branch 'kvm-svm-harden' into HEADPaolo Bonzini
This fixes three issues in nested SVM: 1) in the shutdown_interception() vmexit handler we call kvm_vcpu_reset(). However, if running nested and L1 doesn't intercept shutdown, the function resets vcpu->arch.hflags without properly leaving the nested state. This leaves the vCPU in inconsistent state and later triggers a kernel panic in SVM code. The same bug can likely be triggered by sending INIT via local apic to a vCPU which runs a nested guest. On VMX we are lucky that the issue can't happen because VMX always intercepts triple faults, thus triple fault in L2 will always be redirected to L1. Plus, handle_triple_fault() doesn't reset the vCPU. INIT IPI can't happen on VMX either because INIT events are masked while in VMX mode. Secondarily, KVM doesn't honour SHUTDOWN intercept bit of L1 on SVM. A normal hypervisor should always intercept SHUTDOWN, a unit test on the other hand might want to not do so. Finally, the guest can trigger a kernel non rate limited printk on SVM from the guest, which is fixed as well. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-17KVM: x86: remove exit_int_info warning in svm_handle_exitMaxim Levitsky
It is valid to receive external interrupt and have broken IDT entry, which will lead to #GP with exit_int_into that will contain the index of the IDT entry (e.g any value). Other exceptions can happen as well, like #NP or #SS (if stack switch fails). Thus this warning can be user triggred and has very little value. Cc: stable@vger.kernel.org Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20221103141351.50662-10-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-17KVM: x86: nSVM: leave nested mode on vCPU freeMaxim Levitsky
If the VM was terminated while nested, we free the nested state while the vCPU still is in nested mode. Soon a warning will be added for this condition. Cc: stable@vger.kernel.org Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20221103141351.50662-2-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-15x86/cpu: Restore AMD's DE_CFG MSR after resumeBorislav Petkov
DE_CFG contains the LFENCE serializing bit, restore it on resume too. This is relevant to older families due to the way how they do S3. Unify and correct naming while at it. Fixes: e4d0e84e4907 ("x86/cpu/AMD: Make LFENCE a serializing instruction") Reported-by: Andrew Cooper <Andrew.Cooper3@citrix.com> Reported-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: <stable@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-11-09KVM: x86: SVM: don't save SVM state to SMRAM when VM is not long mode capableMaxim Levitsky
When the guest CPUID doesn't have support for long mode, 32 bit SMRAM layout is used and it has no support for preserving EFER and/or SVM state. Note that this isn't relevant to running 32 bit guests on VM which is long mode capable - such VM can still run 32 bit guests in compatibility mode. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20221025124741.228045-23-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: x86: SVM: use smram structsMaxim Levitsky
Use SMM structs in the SVM code as well, which removes the last user of put_smstate/GET_SMSTATE so remove these macros as well. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20221025124741.228045-22-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: svm: drop explicit return value of kvm_vcpu_mapMaxim Levitsky
if kvm_vcpu_map returns non zero value, error path should be triggered regardless of the exact returned error value. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20221025124741.228045-21-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: x86: smm: use smram structs in the common codeMaxim Levitsky
Use kvm_smram union instad of raw arrays in the common smm code. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20221025124741.228045-18-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: x86: compile out vendor-specific code if SMM is disabledPaolo Bonzini
Vendor-specific code that deals with SMI injection and saving/restoring SMM state is not needed if CONFIG_KVM_SMM is disabled, so remove the four callbacks smi_allowed, enter_smm, leave_smm and enable_smi_window. The users in svm/nested.c and x86.c also have to be compiled out; the amount of #ifdef'ed code is small and it's not worth moving it to smm.c. enter_smm is now used only within #ifdef CONFIG_KVM_SMM, and the stub can therefore be removed. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220929172016.319443-7-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: allow compiling out SMM supportPaolo Bonzini
Some users of KVM implement the UEFI variable store through a paravirtual device that does not require the "SMM lockbox" component of edk2; allow them to compile out system management mode, which is not a full implementation especially in how it interacts with nested virtualization. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220929172016.319443-6-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: x86: start moving SMM-related functions to new filesPaolo Bonzini
Create a new header and source with code related to system management mode emulation. Entry and exit will move there too; for now, opportunistically rename put_smstate to PUT_SMSTATE while moving it to smm.h, and adjust the SMM state saving code. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220929172016.319443-2-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: x86: Handle PERF_CAPABILITIES in common x86's kvm_get_msr_feature()Sean Christopherson
Handle PERF_CAPABILITIES directly in kvm_get_msr_feature() now that the supported value is available in kvm_caps. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221006000314.73240-8-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: x86: Track supported PERF_CAPABILITIES in kvm_capsSean Christopherson
Track KVM's supported PERF_CAPABILITIES in kvm_caps instead of computing the supported capabilities on the fly every time. Using kvm_caps will also allow for future cleanups as the kvm_caps values can be used directly in common x86 code. Signed-off-by: Sean Christopherson <seanjc@google.com> Acked-by: Like Xu <likexu@tencent.com> Message-Id: <20221006000314.73240-6-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09x86, KVM: remove unnecessary argument to x86_virt_spec_ctrl and callersPaolo Bonzini
x86_virt_spec_ctrl only deals with the paravirtualized MSR_IA32_VIRT_SPEC_CTRL now and does not handle MSR_IA32_SPEC_CTRL anymore; remove the corresponding, unused argument. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: SVM: move MSR_IA32_SPEC_CTRL save/restore to assemblyPaolo Bonzini
Restoration of the host IA32_SPEC_CTRL value is probably too late with respect to the return thunk training sequence. With respect to the user/kernel boundary, AMD says, "If software chooses to toggle STIBP (e.g., set STIBP on kernel entry, and clear it on kernel exit), software should set STIBP to 1 before executing the return thunk training sequence." I assume the same requirements apply to the guest/host boundary. The return thunk training sequence is in vmenter.S, quite close to the VM-exit. On hosts without V_SPEC_CTRL, however, the host's IA32_SPEC_CTRL value is not restored until much later. To avoid this, move the restoration of host SPEC_CTRL to assembly and, for consistency, move the restoration of the guest SPEC_CTRL as well. This is not particularly difficult, apart from some care to cover both 32- and 64-bit, and to share code between SEV-ES and normal vmentry. Cc: stable@vger.kernel.org Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk") Suggested-by: Jim Mattson <jmattson@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: SVM: restore host save area from assemblyPaolo Bonzini
Allow access to the percpu area via the GS segment base, which is needed in order to access the saved host spec_ctrl value. In linux-next FILL_RETURN_BUFFER also needs to access percpu data. For simplicity, the physical address of the save area is added to struct svm_cpu_data. Cc: stable@vger.kernel.org Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk") Reported-by: Nathan Chancellor <nathan@kernel.org> Analyzed-by: Andrew Cooper <andrew.cooper3@citrix.com> Tested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: SVM: move guest vmsave/vmload back to assemblyPaolo Bonzini
It is error-prone that code after vmexit cannot access percpu data because GSBASE has not been restored yet. It forces MSR_IA32_SPEC_CTRL save/restore to happen very late, after the predictor untraining sequence, and it gets in the way of return stack depth tracking (a retbleed mitigation that is in linux-next as of 2022-11-09). As a first step towards fixing that, move the VMCB VMSAVE/VMLOAD to assembly, essentially undoing commit fb0c4a4fee5a ("KVM: SVM: move VMLOAD/VMSAVE to C code", 2021-03-15). The reason for that commit was that it made it simpler to use a different VMCB for VMLOAD/VMSAVE versus VMRUN; but that is not a big hassle anymore thanks to the kvm-asm-offsets machinery and other related cleanups. The idea on how to number the exception tables is stolen from a prototype patch by Peter Zijlstra. Cc: stable@vger.kernel.org Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk") Link: <https://lore.kernel.org/all/f571e404-e625-bae1-10e9-449b2eb4cbd8@citrix.com/> Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: SVM: do not allocate struct svm_cpu_data dynamicallyPaolo Bonzini
The svm_data percpu variable is a pointer, but it is allocated via svm_hardware_setup() when KVM is loaded. Unlike hardware_enable() this means that it is never NULL for the whole lifetime of KVM, and static allocation does not waste any memory compared to the status quo. It is also more efficient and more easily handled from assembly code, so do it and don't look back. Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: SVM: remove dead field from struct svm_cpu_dataPaolo Bonzini
The "cpu" field of struct svm_cpu_data has been write-only since commit 4b656b120249 ("KVM: SVM: force new asid on vcpu migration", 2009-08-05). Remove it. Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: SVM: retrieve VMCB from assemblyPaolo Bonzini
Continue moving accesses to struct vcpu_svm to vmenter.S. Reducing the number of arguments limits the chance of mistakes due to different registers used for argument passing in 32- and 64-bit ABIs; pushing the VMCB argument and almost immediately popping it into a different register looks pretty weird. 32-bit ABI is not a concern for __svm_sev_es_vcpu_run() which is 64-bit only; however, it will soon need @svm to save/restore SPEC_CTRL so stay consistent with __svm_vcpu_run() and let them share the same prototype. No functional change intended. Cc: stable@vger.kernel.org Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk") Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-09KVM: SVM: replace regs argument of __svm_vcpu_run() with vcpu_svmPaolo Bonzini
Since registers are reachable through vcpu_svm, and we will need to access more fields of that struct, pass it instead of the regs[] array. No functional change intended. Cc: stable@vger.kernel.org Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk") Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: SVM: Make an event request if INIT or SIPI is pending when GIF is setSean Christopherson
Set KVM_REQ_EVENT if INIT or SIPI is pending when the guest enables GIF. INIT in particular is blocked when GIF=0 and needs to be processed when GIF is toggled to '1'. This bug has been masked by (a) KVM calling ->check_nested_events() in the core run loop and (b) hypervisors toggling GIF from 0=>1 only when entering guest mode (L1 entering L2). Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220921003201.1441511-7-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: x86: Rename inject_pending_events() to kvm_check_and_inject_events()Sean Christopherson
Rename inject_pending_events() to kvm_check_and_inject_events() in order to capture the fact that it handles more than just pending events, and to (mostly) align with kvm_check_nested_events(), which omits the "inject" for brevity. Add a comment above kvm_check_and_inject_events() to provide a high-level synopsis, and to document a virtualization hole (KVM erratum if you will) that exists due to KVM not strictly tracking instruction boundaries with respect to coincident instruction restarts and asynchronous events. No functional change inteded. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Link: https://lore.kernel.org/r/20220830231614.3580124-25-seanjc@google.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: x86: Make kvm_queued_exception a properly named, visible structSean Christopherson
Move the definition of "struct kvm_queued_exception" out of kvm_vcpu_arch in anticipation of adding a second instance in kvm_vcpu_arch to handle exceptions that occur when vectoring an injected exception and are morphed to VM-Exit instead of leading to #DF. Opportunistically take advantage of the churn to rename "nr" to "vector". No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Link: https://lore.kernel.org/r/20220830231614.3580124-15-seanjc@google.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: x86: Rename kvm_x86_ops.queue_exception to inject_exceptionSean Christopherson
Rename the kvm_x86_ops hook for exception injection to better reflect reality, and to align with pretty much every other related function name in KVM. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Link: https://lore.kernel.org/r/20220830231614.3580124-14-seanjc@google.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: Add extra information in kvm_page_fault trace pointWonhyuk Yang
Currently, kvm_page_fault trace point provide fault_address and error code. However it is not enough to find which cpu and instruction cause kvm_page_faults. So add vcpu id and instruction pointer in kvm_page_fault trace point. Cc: Baik Song An <bsahn@etri.re.kr> Cc: Hong Yeon Kim <kimhy@etri.re.kr> Cc: Taeung Song <taeung@reallinux.co.kr> Cc: linuxgeek@linuxgeek.io Signed-off-by: Wonhyuk Yang <vvghjk1234@gmail.com> Link: https://lore.kernel.org/r/20220510071001.87169-1-vvghjk1234@gmail.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: SVM: remove unnecessary check on INIT interceptPaolo Bonzini
Since svm_check_nested_events() is now handling INIT signals, there is no need to latch it until the VMEXIT is injected. The only condition under which INIT signals are latched is GIF=0. Suggested-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Link: https://lore.kernel.org/r/20220819165643.83692-1-pbonzini@redhat.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: SVM: Disable SEV-ES support if MMIO caching is disableSean Christopherson
Disable SEV-ES if MMIO caching is disabled as SEV-ES relies on MMIO SPTEs generating #NPF(RSVD), which are reflected by the CPU into the guest as a #VC. With SEV-ES, the untrusted host, a.k.a. KVM, doesn't have access to the guest instruction stream or register state and so can't directly emulate in response to a #NPF on an emulated MMIO GPA. Disabling MMIO caching means guest accesses to emulated MMIO ranges cause #NPF(!PRESENT), and those flavors of #NPF cause automatic VM-Exits, not #VC. Adjust KVM's MMIO masks to account for the C-bit location prior to doing SEV(-ES) setup, and document that dependency between adjusting the MMIO SPTE mask and SEV(-ES) setup. Fixes: b09763da4dd8 ("KVM: x86/mmu: Add module param to disable MMIO caching (for testing)") Reported-by: Michael Roth <michael.roth@amd.com> Tested-by: Michael Roth <michael.roth@amd.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220803224957.1285926-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-01Merge remote-tracking branch 'kvm/next' into kvm-next-5.20Paolo Bonzini
KVM/s390, KVM/x86 and common infrastructure changes for 5.20 x86: * Permit guests to ignore single-bit ECC errors * Fix races in gfn->pfn cache refresh; do not pin pages tracked by the cache * Intel IPI virtualization * Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS * PEBS virtualization * Simplify PMU emulation by just using PERF_TYPE_RAW events * More accurate event reinjection on SVM (avoid retrying instructions) * Allow getting/setting the state of the speaker port data bit * Refuse starting the kvm-intel module if VM-Entry/VM-Exit controls are inconsistent * "Notify" VM exit (detect microarchitectural hangs) for Intel * Cleanups for MCE MSR emulation s390: * add an interface to provide a hypervisor dump for secure guests * improve selftests to use TAP interface * enable interpretive execution of zPCI instructions (for PCI passthrough) * First part of deferred teardown * CPU Topology * PV attestation * Minor fixes Generic: * new selftests API using struct kvm_vcpu instead of a (vm, id) tuple x86: * Use try_cmpxchg64 instead of cmpxchg64 * Bugfixes * Ignore benign host accesses to PMU MSRs when PMU is disabled * Allow disabling KVM's "MONITOR/MWAIT are NOPs!" behavior * x86/MMU: Allow NX huge pages to be disabled on a per-vm basis * Port eager page splitting to shadow MMU as well * Enable CMCI capability by default and handle injected UCNA errors * Expose pid of vcpu threads in debugfs * x2AVIC support for AMD * cleanup PIO emulation * Fixes for LLDT/LTR emulation * Don't require refcounted "struct page" to create huge SPTEs x86 cleanups: * Use separate namespaces for guest PTEs and shadow PTEs bitmasks * PIO emulation * Reorganize rmap API, mostly around rmap destruction * Do not workaround very old KVM bugs for L0 that runs with nesting enabled * new selftests API for CPUID
2022-07-28KVM: SVM: Do not virtualize MSR accesses for APIC LVTT registerSuravee Suthikulpanit
AMD does not support APIC TSC-deadline timer mode. AVIC hardware will generate GP fault when guest kernel writes 1 to bits [18] of the APIC LVTT register (offset 0x32) to set the timer mode. (Note: bit 18 is reserved on AMD system). Therefore, always intercept and let KVM emulate the MSR accesses. Fixes: f3d7c8aa6882 ("KVM: SVM: Fix x2APIC MSRs interception") Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220725033428.3699-1-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-28KVM: SVM: Fix x2APIC MSRs interceptionSuravee Suthikulpanit
The index for svm_direct_access_msrs was incorrectly initialized with the APIC MMIO register macros. Fix by introducing a macro for calculating x2APIC MSRs. Fixes: 5c127c85472c ("KVM: SVM: Adding support for configuring x2APIC MSRs interception") Cc: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220718083833.222117-1-suravee.suthikulpanit@amd.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-14KVM: x86: Restrict get_mt_mask() to a u8, use KVM_X86_OP_OPTIONAL_RET0Sean Christopherson
Restrict get_mt_mask() to a u8 and reintroduce using a RET0 static_call for the SVM implementation. EPT stores the memtype information in the lower 8 bits (bits 6:3 to be precise), and even returns a shifted u8 without an explicit cast to a larger type; there's no need to return a full u64. Note, RET0 doesn't play nice with a u64 return on 32-bit kernels, see commit bf07be36cd88 ("KVM: x86: do not use KVM_X86_OP_OPTIONAL_RET0 for get_mt_mask"). Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220714153707.3239119-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-14KVM: x86: Add dedicated helper to get CPUID entry with significant indexSean Christopherson
Add a second CPUID helper, kvm_find_cpuid_entry_index(), to handle KVM queries for CPUID leaves whose index _may_ be significant, and drop the index param from the existing kvm_find_cpuid_entry(). Add a WARN in the inner helper, cpuid_entry2_find(), to detect attempts to retrieve a CPUID entry whose index is significant without explicitly providing an index. Using an explicit magic number and letting callers omit the index avoids confusion by eliminating the myriad cases where KVM specifies '0' as a dummy value. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-07-14KVM: SVM: fix task switch emulation on INTn instruction.Maxim Levitsky
Recently KVM's SVM code switched to re-injecting software interrupt events, if something prevented their delivery. Task switch due to task gate in the IDT, however is an exception to this rule, because in this case, INTn instruction causes a task switch intercept and its emulation completes the INTn emulation as well. Add a missing case to task_switch_interception for that. This fixes 32 bit kvm unit test taskswitch2. Fixes: 7e5b5ef8dca322 ("KVM: SVM: Re-inject INTn instead of retrying the insn on "failure"") Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Message-Id: <20220714124453.188655-1-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: x86: nSVM: optimize svm_set_x2apic_msr_interceptionMaxim Levitsky
- Avoid toggling the x2apic msr interception if it is already up to date. - Avoid touching L0 msr bitmap when AVIC is inhibited on entry to the guest mode, because in this case the guest usually uses its own msr bitmap. Later on VM exit, the 1st optimization will allow KVM to skip touching the L0 msr bitmap as well. Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220519102709.24125-18-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: SVM: Introduce hybrid-AVIC modeSuravee Suthikulpanit
Currently, AVIC is inhibited when booting a VM w/ x2APIC support. because AVIC cannot virtualize x2APIC MSR register accesses. However, the AVIC doorbell can be used to accelerate interrupt injection into a running vCPU, while all guest accesses to x2APIC MSRs will be intercepted and emulated by KVM. With hybrid-AVIC support, the APICV_INHIBIT_REASON_X2APIC is no longer enforced. Suggested-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220519102709.24125-14-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: SVM: Introduce logic to (de)activate x2AVIC modeSuravee Suthikulpanit
Introduce logic to (de)activate AVIC, which also allows switching between AVIC to x2AVIC mode at runtime. When an AVIC-enabled guest switches from APIC to x2APIC mode, the SVM driver needs to perform the following steps: 1. Set the x2APIC mode bit for AVIC in VMCB along with the maximum APIC ID support for each mode accodingly. 2. Disable x2APIC MSRs interception in order to allow the hardware to virtualize x2APIC MSRs accesses. Reported-by: kernel test robot <lkp@intel.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220519102709.24125-12-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: SVM: Refresh AVIC configuration when changing APIC modeSuravee Suthikulpanit
AMD AVIC can support xAPIC and x2APIC virtualization, which requires changing x2APIC bit VMCB and MSR intercepton for x2APIC MSRs. Therefore, call avic_refresh_apicv_exec_ctrl() to refresh configuration accordingly. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220519102709.24125-10-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: SVM: Adding support for configuring x2APIC MSRs interceptionSuravee Suthikulpanit
When enabling x2APIC virtualization (x2AVIC), the interception of x2APIC MSRs must be disabled to let the hardware virtualize guest MSR accesses. Current implementation keeps track of list of MSR interception state in the svm_direct_access_msrs array. Therefore, extends the array to include x2APIC MSRs. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220519102709.24125-8-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: SVM: Detect X2APIC virtualization (x2AVIC) supportSuravee Suthikulpanit
Add CPUID check for the x2APIC virtualization (x2AVIC) feature. If available, the SVM driver can support both AVIC and x2AVIC modes when load the kvm_amd driver with avic=1. The operating mode will be determined at runtime depending on the guest APIC mode. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220519102709.24125-4-suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-24KVM: SEV: Init target VMCBs in sev_migrate_fromPeter Gonda
The target VMCBs during an intra-host migration need to correctly setup for running SEV and SEV-ES guests. Add sev_init_vmcb() function and make sev_es_init_vmcb() static. sev_init_vmcb() uses the now private function to init SEV-ES guests VMCBs when needed. Fixes: 0b020f5af092 ("KVM: SEV: Add support for SEV-ES intra host migration") Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Signed-off-by: Peter Gonda <pgonda@google.com> Cc: Marc Orr <marcorr@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Message-Id: <20220623173406.744645-1-pgonda@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-20KVM: x86: Move "apicv_active" into "struct kvm_lapic"Sean Christopherson
Move the per-vCPU apicv_active flag into KVM's local APIC instance. APICv is fully dependent on an in-kernel local APIC, but that's not at all clear when reading the current code due to the flag being stored in the generic kvm_vcpu_arch struct. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220614230548.3852141-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>