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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV updates from Borislav Petkov:
- Some SEV and CC platform helpers cleanup and simplifications now that
the usage patterns are becoming apparent
[ I'm sure I'm the only one that has gets confused by all the TLAs, but
in case there are others: here SEV is AMD's "Secure Encrypted
Virtualization" and CC is generic "Confidential Computing".
There's also Intel SGX (Software Guard Extensions) and TDX (Trust
Domain Extensions), along with all the vendor memory encryption
extensions (SME, TSME, TME, and WTF).
And then we have arm64 with RMA and CCA, and I probably forgot another
dozen or so related acronyms - Linus ]
* tag 'x86_sev_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/coco: Get rid of accessor functions
x86/sev: Get rid of special sev_es_enable_key
x86/coco: Mark cc_platform_has() and descendants noinstr
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 confidential computing update from Borislav Petkov:
- Add support for unaccepted memory as specified in the UEFI spec v2.9.
The gist of it all is that Intel TDX and AMD SEV-SNP confidential
computing guests define the notion of accepting memory before using
it and thus preventing a whole set of attacks against such guests
like memory replay and the like.
There are a couple of strategies of how memory should be accepted -
the current implementation does an on-demand way of accepting.
* tag 'x86_cc_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
virt: sevguest: Add CONFIG_CRYPTO dependency
x86/efi: Safely enable unaccepted memory in UEFI
x86/sev: Add SNP-specific unaccepted memory support
x86/sev: Use large PSC requests if applicable
x86/sev: Allow for use of the early boot GHCB for PSC requests
x86/sev: Put PSC struct on the stack in prep for unaccepted memory support
x86/sev: Fix calculation of end address based on number of pages
x86/tdx: Add unaccepted memory support
x86/tdx: Refactor try_accept_one()
x86/tdx: Make _tdx_hypercall() and __tdx_module_call() available in boot stub
efi/unaccepted: Avoid load_unaligned_zeropad() stepping into unaccepted memory
efi: Add unaccepted memory support
x86/boot/compressed: Handle unaccepted memory
efi/libstub: Implement support for unaccepted memory
efi/x86: Get full memory map in allocate_e820()
mm: Add support for unaccepted memory
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Add SNP-specific hooks to the unaccepted memory support in the boot
path (__accept_memory()) and the core kernel (accept_memory()) in order
to support booting SNP guests when unaccepted memory is present. Without
this support, SNP guests will fail to boot and/or panic() when unaccepted
memory is present in the EFI memory map.
The process of accepting memory under SNP involves invoking the hypervisor
to perform a page state change for the page to private memory and then
issuing a PVALIDATE instruction to accept the page.
Since the boot path and the core kernel paths perform similar operations,
move the pvalidate_pages() and vmgexit_psc() functions into sev-shared.c
to avoid code duplication.
Create the new header file arch/x86/boot/compressed/sev.h because adding
the function declaration to any of the existing SEV related header files
pulls in too many other header files, causing the build to fail.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/a52fa69f460fd1876d70074b20ad68210dfc31dd.1686063086.git.thomas.lendacky@amd.com
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In advance of providing support for unaccepted memory, request 2M Page
State Change (PSC) requests when the address range allows for it. By using
a 2M page size, more PSC operations can be handled in a single request to
the hypervisor. The hypervisor will determine if it can accommodate the
larger request by checking the mapping in the nested page table. If mapped
as a large page, then the 2M page request can be performed, otherwise the
2M page request will be broken down into 512 4K page requests. This is
still more efficient than having the guest perform multiple PSC requests
in order to process the 512 4K pages.
In conjunction with the 2M PSC requests, attempt to perform the associated
PVALIDATE instruction of the page using the 2M page size. If PVALIDATE
fails with a size mismatch, then fallback to validating 512 4K pages. To
do this, page validation is modified to work with the PSC structure and
not just a virtual address range.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/050d17b460dfc237b51d72082e5df4498d3513cb.1686063086.git.thomas.lendacky@amd.com
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Using a GHCB for a page stage change (as opposed to the MSR protocol)
allows for multiple pages to be processed in a single request. In prep
for early PSC requests in support of unaccepted memory, update the
invocation of vmgexit_psc() to be able to use the early boot GHCB and not
just the per-CPU GHCB structure.
In order to use the proper GHCB (early boot vs per-CPU), set a flag that
indicates when the per-CPU GHCBs are available and registered. For APs,
the per-CPU GHCBs are created before they are started and registered upon
startup, so this flag can be used globally for the BSP and APs instead of
creating a per-CPU flag. This will allow for a significant reduction in
the number of MSR protocol page state change requests when accepting
memory.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/d6cbb21f87f81eb8282dd3bf6c34d9698c8a4bbc.1686063086.git.thomas.lendacky@amd.com
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In advance of providing support for unaccepted memory, switch from using
kmalloc() for allocating the Page State Change (PSC) structure to using a
local variable that lives on the stack. This is needed to avoid a possible
recursive call into set_pages_state() if the kmalloc() call requires
(more) memory to be accepted, which would result in a hang.
The current size of the PSC struct is 2,032 bytes. To make the struct more
stack friendly, reduce the number of PSC entries from 253 down to 64,
resulting in a size of 520 bytes. This is a nice compromise on struct size
and total PSC requests while still allowing parallel PSC operations across
vCPUs.
If the reduction in PSC entries results in any kind of performance issue
(that is not seen at the moment), use of a larger static PSC struct, with
fallback to the smaller stack version, can be investigated.
For more background info on this decision, see the subthread in the Link:
tag below.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/lkml/658c455c40e8950cb046dd885dd19dc1c52d060a.1659103274.git.thomas.lendacky@amd.com
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When calculating an end address based on an unsigned int number of pages,
any value greater than or equal to 0x100000 that is shift PAGE_SHIFT bits
results in a 0 value, resulting in an invalid end address. Change the
number of pages variable in various routines from an unsigned int to an
unsigned long to calculate the end address correctly.
Fixes: 5e5ccff60a29 ("x86/sev: Add helper for validating pages in early enc attribute changes")
Fixes: dc3f3d2474b8 ("x86/mm: Validate memory when changing the C-bit")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/6a6e4eea0e1414402bac747744984fa4e9c01bb6.1686063086.git.thomas.lendacky@amd.com
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This is used in the SEV play_dead() implementation to re-online CPUs. But
that has nothing to do with CPU0.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205255.662319599@linutronix.de
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A SEV-ES guest is active on AMD when CC_ATTR_GUEST_STATE_ENCRYPT is set.
I.e., MSR_AMD64_SEV, bit 1, SEV_ES_Enabled. So no need for a special
static key.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230328201712.25852-3-bp@alien8.de
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The GHCB specification declares that the firmware error value for
a guest request will be stored in the lower 32 bits of EXIT_INFO_2. The
upper 32 bits are for the VMM's own error code. The fw_err argument to
snp_guest_issue_request() is thus a misnomer, and callers will need
access to all 64 bits.
The type of unsigned long also causes problems, since sw_exit_info2 is
u64 (unsigned long long) vs the argument's unsigned long*. Change this
type for issuing the guest request. Pass the ioctl command struct's error
field directly instead of in a local variable, since an incomplete guest
request may not set the error code, and uninitialized stack memory would
be written back to user space.
The firmware might not even be called, so bookend the call with the no
firmware call error and clear the error.
Since the "fw_err" field is really exitinfo2 split into the upper bits'
vmm error code and lower bits' firmware error code, convert the 64 bit
value to a union.
[ bp:
- Massage commit message
- adjust code
- Fix a build issue as
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202303070609.vX6wp2Af-lkp@intel.com
- print exitinfo2 in hex
Tom:
- Correct -EIO exit case. ]
Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230214164638.1189804-5-dionnaglaze@google.com
Link: https://lore.kernel.org/r/20230307192449.24732-12-bp@alien8.de
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A potentially malicious SEV guest can constantly hammer the hypervisor
using this driver to send down requests and thus prevent or at least
considerably hinder other guests from issuing requests to the secure
processor which is a shared platform resource.
Therefore, the host is permitted and encouraged to throttle such guest
requests.
Add the capability to handle the case when the hypervisor throttles
excessive numbers of requests issued by the guest. Otherwise, the VM
platform communication key will be disabled, preventing the guest from
attesting itself.
Realistically speaking, a well-behaved guest should not even care about
throttling. During its lifetime, it would end up issuing a handful of
requests which the hardware can easily handle.
This is more to address the case of a malicious guest. Such guest should
get throttled and if its VMPCK gets disabled, then that's its own
wrongdoing and perhaps that guest even deserves it.
To the implementation: the hypervisor signals with SNP_GUEST_REQ_ERR_BUSY
that the guest requests should be throttled. That error code is returned
in the upper 32-bit half of exitinfo2 and this is part of the GHCB spec
v2.
So the guest is given a throttling period of 1 minute in which it
retries the request every 2 seconds. This is a good default but if it
turns out to not pan out in practice, it can be tweaked later.
For safety, since the encryption algorithm in GHCBv2 is AES_GCM, control
must remain in the kernel to complete the request with the current
sequence number. Returning without finishing the request allows the
guest to make another request but with different message contents. This
is IV reuse, and breaks cryptographic protections.
[ bp:
- Rewrite commit message and do a simplified version.
- The stable tags are supposed to denote that a cleanup should go
upfront before backporting this so that any future fixes to this
can preserve the sanity of the backporter(s). ]
Fixes: d5af44dde546 ("x86/sev: Provide support for SNP guest request NAEs")
Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
Co-developed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org> # d6fd48eff750 ("virt/coco/sev-guest: Check SEV_SNP attribute at probe time")
Cc: <stable@kernel.org> # 970ab823743f (" virt/coco/sev-guest: Simplify extended guest request handling")
Cc: <stable@kernel.org> # c5a338274bdb ("virt/coco/sev-guest: Remove the disable_vmpck label in handle_guest_request()")
Cc: <stable@kernel.org> # 0fdb6cc7c89c ("virt/coco/sev-guest: Carve out the request issuing logic into a helper")
Cc: <stable@kernel.org> # d25bae7dc7b0 ("virt/coco/sev-guest: Do some code style cleanups")
Cc: <stable@kernel.org> # fa4ae42cc60a ("virt/coco/sev-guest: Convert the sw_exit_info_2 checking to a switch-case")
Link: https://lore.kernel.org/r/20230214164638.1189804-2-dionnaglaze@google.com
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snp_issue_guest_request() checks the value returned by the hypervisor in
sw_exit_info_2 and returns a different error depending on it.
Convert those checks into a switch-case to make it more readable when
more error values are going to be checked in the future.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230307192449.24732-8-bp@alien8.de
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Return a specific error code - -ENOSPC - to signal the too small cert
data buffer instead of checking exit code and exitinfo2.
While at it, hoist the *fw_err assignment in snp_issue_guest_request()
so that a proper error value is returned to the callers.
[ Tom: check override_err instead of err. ]
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230307192449.24732-4-bp@alien8.de
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No need to check it on every ioctl. And yes, this is a common SEV driver
but it does only SNP-specific operations currently. This can be
revisited later, when more use cases appear.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230307192449.24732-3-bp@alien8.de
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from MMIO trace type
Both <linux/mmiotrace.h> and <asm/insn-eval.h> define various MMIO_ enum constants,
whose namespace overlaps.
Rename the <asm/insn-eval.h> ones to have a INSN_ prefix, so that the headers can be
used from the same source file.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230101162910.710293-2-Jason@zx2c4.com
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Mark both the function prototype and definition as noreturn in order to
prevent the compiler from doing transformations which confuse objtool
like so:
vmlinux.o: warning: objtool: sme_enable+0x71: unreachable instruction
This triggers with gcc-12.
Add it and sev_es_terminate() to the objtool noreturn tracking array
too. Sort it while at it.
Suggested-by: Michael Matz <matz@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220824152420.20547-1-bp@alien8.de
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When running identity-mapped and depending on the kernel configuration,
it is possible that the compiler uses jump tables when generating code
for cc_platform_has().
This causes a boot failure because the jump table uses un-mapped kernel
virtual addresses, not identity-mapped addresses. This has been seen
with CONFIG_RETPOLINE=n.
Similar to sme_encrypt_kernel(), use an open-coded direct check for the
status of SNP rather than trying to eliminate the jump table. This
preserves any code optimization in cc_platform_has() that can be useful
post boot. It also limits the changes to SEV-specific files so that
future compiler features won't necessarily require possible build changes
just because they are not compatible with running identity-mapped.
[ bp: Massage commit message. ]
Fixes: 5e5ccff60a29 ("x86/sev: Add helper for validating pages in early enc attribute changes")
Reported-by: Sean Christopherson <seanjc@google.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 5.19.x
Link: https://lore.kernel.org/all/YqfabnTRxFSM+LoX@google.com/
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This reverts commit 007faec014cb5d26983c1f86fd08c6539b41392e.
Now that hyperv does its own protocol negotiation:
49d6a3c062a1 ("x86/Hyper-V: Add SEV negotiate protocol support in Isolation VM")
revert this exposure of the sev_es_ghcb_hv_call() helper.
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by：Tianyu Lan <tiala@microsoft.com>
Link: https://lore.kernel.org/r/20220614014553.1915929-1-ltykernel@gmail.com
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Fix:
arch/x86/kernel/sev.c:605:16: warning: incorrect type in assignment (different address spaces)
arch/x86/kernel/sev.c:605:16: expected struct snp_secrets_page_layout *layout
arch/x86/kernel/sev.c:605:16: got void [noderef] __iomem *[assigned] mem
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/202205022233.XgNDR7WR-lkp@intel.com
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The GHCB specification section 2.7 states that when SEV-SNP is enabled,
a guest should not rely on the hypervisor to provide the address of the
AP jump table. Instead, if a guest BIOS wants to provide an AP jump
table, it should record the address in the SNP secrets page so the guest
operating system can obtain it directly from there.
Fix this on the guest kernel side by having SNP guests use the AP jump
table address published in the secrets page rather than issuing a GHCB
request to get it.
[ mroth:
- Improve error handling when ioremap()/memremap() return NULL
- Don't mix function calls with declarations
- Add missing __init
- Tweak commit message ]
Fixes: 0afb6b660a6b ("x86/sev: Use SEV-SNP AP creation to start secondary CPUs")
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220422135624.114172-3-michael.roth@amd.com
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Currently, get_secrets_page() is only reachable from the following call
chain:
__init snp_init_platform_device():
get_secrets_page()
so mark it as __init as well. This is also needed since it calls
early_memremap(), which is also an __init routine.
Similarly, get_jump_table_addr() is only reachable from the following
call chain:
__init setup_real_mode():
sme_sev_setup_real_mode():
sev_es_setup_ap_jump_table():
get_jump_table_addr()
so mark get_jump_table_addr() and everything up that call chain as
__init as well. This is also needed since future patches will add a
call to get_secrets_page(), which needs to be __init due to the reasons
stated above.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220422135624.114172-2-michael.roth@amd.com
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During patch review, it was decided the SNP guest driver name should not
be SEV-SNP specific, but should be generic for use with anything SEV.
However, this feedback was missed and the driver name, and many of the
driver functions and structures, are SEV-SNP name specific. Rename the
driver to "sev-guest" (to match the misc device that is created) and
update some of the function and structure names, too.
While in the file, adjust the one pr_err() message to be a dev_err()
message so that the message, if issued, uses the driver name.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/307710bb5515c9088a19fd0b930268c7300479b2.1650464054.git.thomas.lendacky@amd.com
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Replace the halt loop in handle_vc_boot_ghcb() with an
sev_es_terminate(). The HLT gives the system no indication the guest is
unhappy. The termination request will signal there was an error during
VC handling during boot.
[ bp: Update it to pass the reason set too. ]
Signed-off-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20220317211913.1397427-1-pgonda@google.com
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Version 2 of the GHCB specification provides a Non Automatic Exit (NAE)
event type that can be used by the SEV-SNP guest to communicate with the
PSP without risk from a malicious hypervisor who wishes to read, alter,
drop or replay the messages sent.
SNP_LAUNCH_UPDATE can insert two special pages into the guest’s memory:
the secrets page and the CPUID page. The PSP firmware populates the
contents of the secrets page. The secrets page contains encryption keys
used by the guest to interact with the firmware. Because the secrets
page is encrypted with the guest’s memory encryption key, the hypervisor
cannot read the keys. See SEV-SNP firmware spec for further details on
the secrets page format.
Create a platform device that the SEV-SNP guest driver can bind to get
the platform resources such as encryption key and message id to use to
communicate with the PSP. The SEV-SNP guest driver provides a userspace
interface to get the attestation report, key derivation, extended
attestation report etc.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-43-brijesh.singh@amd.com
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Version 2 of GHCB specification provides SNP_GUEST_REQUEST and
SNP_EXT_GUEST_REQUEST NAE that can be used by the SNP guest to
communicate with the PSP.
While at it, add a snp_issue_guest_request() helper that will be used by
driver or other subsystem to issue the request to PSP.
See SEV-SNP firmware and GHCB spec for more details.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-42-brijesh.singh@amd.com
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For debugging purposes it is very useful to have a way to see the full
contents of the SNP CPUID table provided to a guest. Add an sev=debug
kernel command-line option to do so.
Also introduce some infrastructure so that additional options can be
specified via sev=option1[,option2] over time in a consistent manner.
[ bp: Massage, simplify string parsing. ]
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-41-brijesh.singh@amd.com
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SEV-SNP guests will be provided the location of special 'secrets' and
'CPUID' pages via the Confidential Computing blob. This blob is
provided to the run-time kernel either through a boot_params field that
was initialized by the boot/compressed kernel, or via a setup_data
structure as defined by the Linux Boot Protocol.
Locate the Confidential Computing blob from these sources and, if found,
use the provided CPUID page/table address to create a copy that the
run-time kernel will use when servicing CPUID instructions via a #VC
handler.
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-40-brijesh.singh@amd.com
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Initial/preliminary detection of SEV-SNP is done via the Confidential
Computing blob. Check for it prior to the normal SEV/SME feature
initialization, and add some sanity checks to confirm it agrees with
SEV-SNP CPUID/MSR bits.
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-39-brijesh.singh@amd.com
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This code will also be used later for SEV-SNP-validated CPUID code in
some cases, so move it to a common helper.
While here, also add a check to terminate in cases where the CPUID
function/subfunction is indexed and the subfunction is non-zero, since
the GHCB MSR protocol does not support non-zero subfunctions.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-32-brijesh.singh@amd.com
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To provide a more secure way to start APs under SEV-SNP, use the SEV-SNP
AP Creation NAE event. This allows for guest control over the AP register
state rather than trusting the hypervisor with the SEV-ES Jump Table
address.
During native_smp_prepare_cpus(), invoke an SEV-SNP function that, if
SEV-SNP is active, will set/override apic->wakeup_secondary_cpu. This
will allow the SEV-SNP AP Creation NAE event method to be used to boot
the APs. As a result of installing the override when SEV-SNP is active,
this method of starting the APs becomes the required method. The override
function will fail to start the AP if the hypervisor does not have
support for AP creation.
[ bp: Work in forgotten review comments. ]
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-23-brijesh.singh@amd.com
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Add the needed functionality to change pages state from shared
to private and vice-versa using the Page State Change VMGEXIT as
documented in the GHCB spec.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-22-brijesh.singh@amd.com
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early_set_memory_{encrypted,decrypted}() are used for changing the page
state from decrypted (shared) to encrypted (private) and vice versa.
When SEV-SNP is active, the page state transition needs to go through
additional steps.
If the page is transitioned from shared to private, then perform the
following after the encryption attribute is set in the page table:
1. Issue the page state change VMGEXIT to add the page as a private
in the RMP table.
2. Validate the page after its successfully added in the RMP table.
To maintain the security guarantees, if the page is transitioned from
private to shared, then perform the following before clearing the
encryption attribute from the page table.
1. Invalidate the page.
2. Issue the page state change VMGEXIT to make the page shared in the
RMP table.
early_set_memory_{encrypted,decrypted}() can be called before the GHCB
is setup so use the SNP page state MSR protocol VMGEXIT defined in the
GHCB specification to request the page state change in the RMP table.
While at it, add a helper snp_prep_memory() which will be used in
probe_roms(), in a later patch.
[ bp: Massage commit message. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Link: https://lore.kernel.org/r/20220307213356.2797205-19-brijesh.singh@amd.com
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The SEV-SNP guest is required by the GHCB spec to register the GHCB's
Guest Physical Address (GPA). This is because the hypervisor may prefer
that a guest uses a consistent and/or specific GPA for the GHCB associated
with a vCPU. For more information, see the GHCB specification section
"GHCB GPA Registration".
[ bp: Cleanup comments. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-18-brijesh.singh@amd.com
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Version 2 of the GHCB specification added the advertisement of features
that are supported by the hypervisor. If the hypervisor supports SEV-SNP
then it must set the SEV-SNP features bit to indicate that the base
functionality is supported.
Check that feature bit while establishing the GHCB; if failed, terminate
the guest.
Version 2 of the GHCB specification adds several new Non-Automatic Exits
(NAEs), most of them are optional except the hypervisor feature. Now
that the hypervisor feature NAE is implemented, bump the GHCB maximum
supported protocol version.
While at it, move the GHCB protocol negotiation check from the #VC
exception handler to sev_enable() so that all feature detection happens
before the first #VC exception.
While at it, document why the GHCB page cannot be setup from
load_stage2_idt().
[ bp: Massage commit message. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-13-brijesh.singh@amd.com
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The GHCB specification defines the reason code for reason set 0. The
reason codes defined in the set 0 do not cover all possible causes for a
guest to request termination.
The reason sets 1 to 255 are reserved for the vendor-specific codes.
Reserve the reason set 1 for the Linux guest. Define the error codes for
reason set 1 so that one can have meaningful termination reasons and thus
better guest failure diagnosis.
While at it, change sev_es_terminate() to accept a reason set parameter.
[ bp: Massage commit message. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Link: https://lore.kernel.org/r/20220307213356.2797205-11-brijesh.singh@amd.com
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull misc x86 updates from Borislav Petkov:
"The pile which we cannot find the proper topic for so we stick it in
x86/misc:
- Add support for decoding instructions which do MMIO accesses in
order to use it in SEV and TDX guests
- An include fix and reorg to allow for removing set_fs in UML later"
* tag 'x86_misc_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mtrr: Remove the mtrr_bp_init() stub
x86/sev-es: Use insn_decode_mmio() for MMIO implementation
x86/insn-eval: Introduce insn_decode_mmio()
x86/insn-eval: Introduce insn_get_modrm_reg_ptr()
x86/insn-eval: Handle insn_get_opcode() failure
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV updates from Borislav Petkov:
"The accumulated pile of x86/sev generalizations and cleanups:
- Share the SEV string unrolling logic with TDX as TDX guests need it
too
- Cleanups and generalzation of code shared by SEV and TDX"
* tag 'x86_sev_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev: Move common memory encryption code to mem_encrypt.c
x86/sev: Rename mem_encrypt.c to mem_encrypt_amd.c
x86/sev: Use CC_ATTR attribute to generalize string I/O unroll
x86/sev: Remove do_early_exception() forward declarations
x86/head64: Carve out the guest encryption postprocessing into a helper
x86/sev: Get rid of excessive use of defines
x86/sev: Shorten GHCB terminate macro names
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Properly type the operands being passed to __put_user()/__get_user().
Otherwise, these routines truncate data for dependent instructions
(e.g., INSW) and only read/write one byte.
This has been tested by sending a string with REP OUTSW to a port and
then reading it back in with REP INSW on the same port.
Previous behavior was to only send and receive the first char of the
size. For example, word operations for "abcd" would only read/write
"ac". With change, the full string is now written and read back.
Fixes: f980f9c31a923 (x86/sev-es: Compile early handler code into kernel image)
Signed-off-by: Michael Sterritt <sterritt@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Reviewed-by: Peter Gonda <pgonda@google.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Link: https://lkml.kernel.org/r/20211119232757.176201-1-sterritt@google.com
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Switch SEV implementation to insn_decode_mmio(). The helper is going
to be used by TDX too.
No functional changes.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Tested-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20211130184933.31005-5-kirill.shutemov@linux.intel.com
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There's a perfectly fine prototype in the asm/setup.h header. Use it.
No functional changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211110220731.2396491-8-brijesh.singh@amd.com
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Shorten macro names for improved readability.
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Link: https://lkml.kernel.org/r/20211110220731.2396491-5-brijesh.singh@amd.com
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Borislav Petkov:
- Do not #GP on userspace use of CLI/STI but pretend it was a NOP to
keep old userspace from breaking. Adjust the corresponding iopl
selftest to that.
- Improve stack overflow warnings to say which stack got overflowed and
raise the exception stack sizes to 2 pages since overflowing the
single page of exception stack is very easy to do nowadays with all
the tracing machinery enabled. With that, rip out the custom mapping
of AMD SEV's too.
- A bunch of changes in preparation for FGKASLR like supporting more
than 64K section headers in the relocs tool, correct ORC lookup table
size to cover the whole kernel .text and other adjustments.
* tag 'x86_core_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
selftests/x86/iopl: Adjust to the faked iopl CLI/STI usage
vmlinux.lds.h: Have ORC lookup cover entire _etext - _stext
x86/boot/compressed: Avoid duplicate malloc() implementations
x86/boot: Allow a "silent" kaslr random byte fetch
x86/tools/relocs: Support >64K section headers
x86/sev: Make the #VC exception stacks part of the default stacks storage
x86: Increase exception stack sizes
x86/mm/64: Improve stack overflow warnings
x86/iopl: Fake iopl(3) CLI/STI usage
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV updates from Borislav Petkov:
- Export sev_es_ghcb_hv_call() so that HyperV Isolation VMs can use it
too
- Non-urgent fixes and cleanups
* tag 'x86_sev_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV
x86/sev: Allow #VC exceptions on the VC2 stack
x86/sev: Fix stack type check in vc_switch_off_ist()
x86/sme: Use #define USE_EARLY_PGTABLE_L5 in mem_encrypt_identity.c
x86/sev: Carve out HV call's return value verification
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull generic confidential computing updates from Borislav Petkov:
"Add an interface called cc_platform_has() which is supposed to be used
by confidential computing solutions to query different aspects of the
system.
The intent behind it is to unify testing of such aspects instead of
having each confidential computing solution add its own set of tests
to code paths in the kernel, leading to an unwieldy mess"
* tag 'x86_cc_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
treewide: Replace the use of mem_encrypt_active() with cc_platform_has()
x86/sev: Replace occurrences of sev_es_active() with cc_platform_has()
x86/sev: Replace occurrences of sev_active() with cc_platform_has()
x86/sme: Replace occurrences of sme_active() with cc_platform_has()
powerpc/pseries/svm: Add a powerpc version of cc_platform_has()
x86/sev: Add an x86 version of cc_platform_has()
arch/cc: Introduce a function to check for confidential computing features
x86/ioremap: Selectively build arch override encryption functions
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Hyper-V needs to issue the GHCB HV call in order to read/write MSRs in
Isolation VMs. For that, expose sev_es_ghcb_hv_call().
The Hyper-V Isolation VMs are unenlightened guests and run a paravisor
at VMPL0 for communicating. GHCB pages are being allocated and set up
by that paravisor. Linux gets the GHCB page's physical address via
MSR_AMD64_SEV_ES_GHCB from the paravisor and should not change it.
Add a @set_ghcb_msr parameter to sev_es_ghcb_hv_call() to control
whether the function should set the GHCB's address prior to the call or
not and export that function for use by HyperV.
[ bp: - Massage commit message
- add a struct ghcb forward declaration to fix randconfig builds. ]
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-6-ltykernel@gmail.com
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When code running on the VC2 stack causes a nested VC exception, the
handler will not handle it as expected but goes again into the error
path.
The result is that the panic() call happening when the VC exception
was raised in an invalid context is called recursively. Fix this by
checking the interrupted stack too and only call panic if it is not
the VC2 stack.
[ bp: Fixup comment. ]
Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler")
Reported-by: Xinyang Ge <xing@microsoft.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211021080833.30875-3-joro@8bytes.org
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Include the header which only provides the XCR accessors. That's all what
is needed here.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011539.896573039@linutronix.de
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The size of the exception stacks was increased by the commit in Fixes,
resulting in stack sizes greater than a page in size. The #VC exception
handling was only mapping the first (bottom) page, resulting in an
SEV-ES guest failing to boot.
Make the #VC exception stacks part of the default exception stacks
storage and allocate them with a CONFIG_AMD_MEM_ENCRYPT=y .config. Map
them only when a SEV-ES guest has been detected.
Rip out the custom VC stacks mapping and storage code.
[ bp: Steal and adapt Tom's commit message. ]
Fixes: 7fae4c24a2b8 ("x86: Increase exception stack sizes")
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Link: https://lkml.kernel.org/r/YVt1IMjIs7pIZTRR@zn.tnic
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Replace uses of sev_es_active() with the more generic cc_platform_has()
using CC_ATTR_GUEST_STATE_ENCRYPT. If future support is added for other
memory encyrption techonologies, the use of CC_ATTR_GUEST_STATE_ENCRYPT
can be updated, as required.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210928191009.32551-8-bp@alien8.de
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The source file has been renamed froms sev-es.c to sev.c, but the
messages are still prefixed with "SEV-ES: ". Change that to "SEV: " to
make it consistent.
Fixes: e759959fe3b8 ("x86/sev-es: Rename sev-es.{ch} to sev.{ch}")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210622144825.27588-4-joro@8bytes.org
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