<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/x86/coco, branch v6.16</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>x86/sev: Work around broken noinstr on GCC</title>
<updated>2025-07-15T08:12:25+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2025-07-14T07:34:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6b995d01683feae619aa3263d18a6aa19bface16'/>
<id>6b995d01683feae619aa3263d18a6aa19bface16</id>
<content type='text'>
Forcibly disable KCSAN for the sev-nmi.c source file, which only
contains functions annotated as 'noinstr' but is emitted with calls to
KCSAN instrumentation nonetheless. E.g.,

  vmlinux.o: error: objtool: __sev_es_nmi_complete+0x58: call to __kcsan_check_access() leaves .noinstr.text section
  make[2]: *** [/usr/local/google/home/ardb/linux/scripts/Makefile.vmlinux_o:72: vmlinux.o] Error 1

Fixes: a3cbbb4717e1 ("x86/boot: Move SEV startup code into startup/")
Reported-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Acked-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Tested-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Link: https://lore.kernel.org/20250714073402.4107091-2-ardb+git@google.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Forcibly disable KCSAN for the sev-nmi.c source file, which only
contains functions annotated as 'noinstr' but is emitted with calls to
KCSAN instrumentation nonetheless. E.g.,

  vmlinux.o: error: objtool: __sev_es_nmi_complete+0x58: call to __kcsan_check_access() leaves .noinstr.text section
  make[2]: *** [/usr/local/google/home/ardb/linux/scripts/Makefile.vmlinux_o:72: vmlinux.o] Error 1

Fixes: a3cbbb4717e1 ("x86/boot: Move SEV startup code into startup/")
Reported-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Acked-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Tested-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Link: https://lore.kernel.org/20250714073402.4107091-2-ardb+git@google.com
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/sev: Use TSC_FACTOR for Secure TSC frequency calculation</title>
<updated>2025-06-30T22:29:27+00:00</updated>
<author>
<name>Nikunj A Dadhania</name>
<email>nikunj@amd.com</email>
</author>
<published>2025-06-30T08:18:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=52e1a03e6cf61ae165f59f41c44394a653a0a788'/>
<id>52e1a03e6cf61ae165f59f41c44394a653a0a788</id>
<content type='text'>
When using Secure TSC, the GUEST_TSC_FREQ MSR reports a frequency based on
the nominal P0 frequency, which deviates slightly (typically ~0.2%) from
the actual mean TSC frequency due to clocking parameters.

Over extended VM uptime, this discrepancy accumulates, causing clock skew
between the hypervisor and a SEV-SNP VM, leading to early timer interrupts as
perceived by the guest.

The guest kernel relies on the reported nominal frequency for TSC-based
timekeeping, while the actual frequency set during SNP_LAUNCH_START may
differ. This mismatch results in inaccurate time calculations, causing the
guest to perceive hrtimers as firing earlier than expected.

Utilize the TSC_FACTOR from the SEV firmware's secrets page (see "Secrets
Page Format" in the SNP Firmware ABI Specification) to calculate the mean
TSC frequency, ensuring accurate timekeeping and mitigating clock skew in
SEV-SNP VMs.

Use early_ioremap_encrypted() to map the secrets page as
ioremap_encrypted() uses kmalloc() which is not available during early TSC
initialization and causes a panic.

  [ bp: Drop the silly dummy var:
    https://lore.kernel.org/r/20250630192726.GBaGLlHl84xIopx4Pt@fat_crate.local ]

Fixes: 73bbf3b0fbba ("x86/tsc: Init the TSC for Secure TSC guests")
Signed-off-by: Nikunj A Dadhania &lt;nikunj@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250630081858.485187-1-nikunj@amd.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When using Secure TSC, the GUEST_TSC_FREQ MSR reports a frequency based on
the nominal P0 frequency, which deviates slightly (typically ~0.2%) from
the actual mean TSC frequency due to clocking parameters.

Over extended VM uptime, this discrepancy accumulates, causing clock skew
between the hypervisor and a SEV-SNP VM, leading to early timer interrupts as
perceived by the guest.

The guest kernel relies on the reported nominal frequency for TSC-based
timekeeping, while the actual frequency set during SNP_LAUNCH_START may
differ. This mismatch results in inaccurate time calculations, causing the
guest to perceive hrtimers as firing earlier than expected.

Utilize the TSC_FACTOR from the SEV firmware's secrets page (see "Secrets
Page Format" in the SNP Firmware ABI Specification) to calculate the mean
TSC frequency, ensuring accurate timekeeping and mitigating clock skew in
SEV-SNP VMs.

Use early_ioremap_encrypted() to map the secrets page as
ioremap_encrypted() uses kmalloc() which is not available during early TSC
initialization and causes a panic.

  [ bp: Drop the silly dummy var:
    https://lore.kernel.org/r/20250630192726.GBaGLlHl84xIopx4Pt@fat_crate.local ]

Fixes: 73bbf3b0fbba ("x86/tsc: Init the TSC for Secure TSC guests")
Signed-off-by: Nikunj A Dadhania &lt;nikunj@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250630081858.485187-1-nikunj@amd.com
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'hyperv-next-signed-20250602' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux</title>
<updated>2025-06-03T15:39:20+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-06-03T15:39:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c00b28502470b7677c2f4ee2e9c899205fa78e27'/>
<id>c00b28502470b7677c2f4ee2e9c899205fa78e27</id>
<content type='text'>
Pull hyperv updates from Wei Liu:

 - Support for Virtual Trust Level (VTL) on arm64 (Roman Kisel)

 - Fixes for Hyper-V UIO driver (Long Li)

 - Fixes for Hyper-V PCI driver (Michael Kelley)

 - Select CONFIG_SYSFB for Hyper-V guests (Michael Kelley)

 - Documentation updates for Hyper-V VMBus (Michael Kelley)

 - Enhance logging for hv_kvp_daemon (Shradha Gupta)

* tag 'hyperv-next-signed-20250602' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (23 commits)
  Drivers: hv: Always select CONFIG_SYSFB for Hyper-V guests
  Drivers: hv: vmbus: Add comments about races with "channels" sysfs dir
  Documentation: hyperv: Update VMBus doc with new features and info
  PCI: hv: Remove unnecessary flex array in struct pci_packet
  Drivers: hv: Remove hv_alloc/free_* helpers
  Drivers: hv: Use kzalloc for panic page allocation
  uio_hv_generic: Align ring size to system page
  uio_hv_generic: Use correct size for interrupt and monitor pages
  Drivers: hv: Allocate interrupt and monitor pages aligned to system page boundary
  arch/x86: Provide the CPU number in the wakeup AP callback
  x86/hyperv: Fix APIC ID and VP index confusion in hv_snp_boot_ap()
  PCI: hv: Get vPCI MSI IRQ domain from DeviceTree
  ACPI: irq: Introduce acpi_get_gsi_dispatcher()
  Drivers: hv: vmbus: Introduce hv_get_vmbus_root_device()
  Drivers: hv: vmbus: Get the IRQ number from DeviceTree
  dt-bindings: microsoft,vmbus: Add interrupt and DMA coherence properties
  arm64, x86: hyperv: Report the VTL the system boots in
  arm64: hyperv: Initialize the Virtual Trust Level field
  Drivers: hv: Provide arch-neutral implementation of get_vtl()
  Drivers: hv: Enable VTL mode for arm64
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull hyperv updates from Wei Liu:

 - Support for Virtual Trust Level (VTL) on arm64 (Roman Kisel)

 - Fixes for Hyper-V UIO driver (Long Li)

 - Fixes for Hyper-V PCI driver (Michael Kelley)

 - Select CONFIG_SYSFB for Hyper-V guests (Michael Kelley)

 - Documentation updates for Hyper-V VMBus (Michael Kelley)

 - Enhance logging for hv_kvp_daemon (Shradha Gupta)

* tag 'hyperv-next-signed-20250602' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (23 commits)
  Drivers: hv: Always select CONFIG_SYSFB for Hyper-V guests
  Drivers: hv: vmbus: Add comments about races with "channels" sysfs dir
  Documentation: hyperv: Update VMBus doc with new features and info
  PCI: hv: Remove unnecessary flex array in struct pci_packet
  Drivers: hv: Remove hv_alloc/free_* helpers
  Drivers: hv: Use kzalloc for panic page allocation
  uio_hv_generic: Align ring size to system page
  uio_hv_generic: Use correct size for interrupt and monitor pages
  Drivers: hv: Allocate interrupt and monitor pages aligned to system page boundary
  arch/x86: Provide the CPU number in the wakeup AP callback
  x86/hyperv: Fix APIC ID and VP index confusion in hv_snp_boot_ap()
  PCI: hv: Get vPCI MSI IRQ domain from DeviceTree
  ACPI: irq: Introduce acpi_get_gsi_dispatcher()
  Drivers: hv: vmbus: Introduce hv_get_vmbus_root_device()
  Drivers: hv: vmbus: Get the IRQ number from DeviceTree
  dt-bindings: microsoft,vmbus: Add interrupt and DMA coherence properties
  arm64, x86: hyperv: Report the VTL the system boots in
  arm64: hyperv: Initialize the Virtual Trust Level field
  Drivers: hv: Provide arch-neutral implementation of get_vtl()
  Drivers: hv: Enable VTL mode for arm64
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'tsm-for-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/devsec/tsm</title>
<updated>2025-05-30T04:21:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-05-30T04:21:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ae5ec8adb8ec9c2aa916f853737c101faa87e5ba'/>
<id>ae5ec8adb8ec9c2aa916f853737c101faa87e5ba</id>
<content type='text'>
Pull trusted security manager (TSM) updates from Dan Williams:

 - Add a general sysfs scheme for publishing "Measurement" values
   provided by the architecture's TEE Security Manager. Use it to
   publish TDX "Runtime Measurement Registers" ("RTMRs") that either
   maintain a hash of stored values (similar to a TPM PCR) or provide
   statically provisioned data. These measurements are validated by a
   relying party.

 - Reorganize the drivers/virt/coco/ directory for "host" and "guest"
   shared infrastructure.

 - Fix a configfs-tsm-report unregister bug

 - With CONFIG_TSM_MEASUREMENTS joining CONFIG_TSM_REPORTS and in
   anticipation of more shared "TSM" infrastructure arriving, rename the
   maintainer entry to "TRUSTED SECURITY MODULE (TSM) INFRASTRUCTURE".

* tag 'tsm-for-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/devsec/tsm:
  tsm-mr: Fix init breakage after bin_attrs constification by scoping non-const pointers to init phase
  sample/tsm-mr: Fix missing static for sample_report
  virt: tdx-guest: Transition to scoped_cond_guard for mutex operations
  virt: tdx-guest: Refactor and streamline TDREPORT generation
  virt: tdx-guest: Expose TDX MRs as sysfs attributes
  x86/tdx: tdx_mcall_get_report0: Return -EBUSY on TDCALL_OPERAND_BUSY error
  x86/tdx: Add tdx_mcall_extend_rtmr() interface
  tsm-mr: Add tsm-mr sample code
  tsm-mr: Add TVM Measurement Register support
  configfs-tsm-report: Fix NULL dereference of tsm_ops
  coco/guest: Move shared guest CC infrastructure to drivers/virt/coco/guest/
  configfs-tsm: Namespace TSM report symbols
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull trusted security manager (TSM) updates from Dan Williams:

 - Add a general sysfs scheme for publishing "Measurement" values
   provided by the architecture's TEE Security Manager. Use it to
   publish TDX "Runtime Measurement Registers" ("RTMRs") that either
   maintain a hash of stored values (similar to a TPM PCR) or provide
   statically provisioned data. These measurements are validated by a
   relying party.

 - Reorganize the drivers/virt/coco/ directory for "host" and "guest"
   shared infrastructure.

 - Fix a configfs-tsm-report unregister bug

 - With CONFIG_TSM_MEASUREMENTS joining CONFIG_TSM_REPORTS and in
   anticipation of more shared "TSM" infrastructure arriving, rename the
   maintainer entry to "TRUSTED SECURITY MODULE (TSM) INFRASTRUCTURE".

* tag 'tsm-for-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/devsec/tsm:
  tsm-mr: Fix init breakage after bin_attrs constification by scoping non-const pointers to init phase
  sample/tsm-mr: Fix missing static for sample_report
  virt: tdx-guest: Transition to scoped_cond_guard for mutex operations
  virt: tdx-guest: Refactor and streamline TDREPORT generation
  virt: tdx-guest: Expose TDX MRs as sysfs attributes
  x86/tdx: tdx_mcall_get_report0: Return -EBUSY on TDCALL_OPERAND_BUSY error
  x86/tdx: Add tdx_mcall_extend_rtmr() interface
  tsm-mr: Add tsm-mr sample code
  tsm-mr: Add TVM Measurement Register support
  configfs-tsm-report: Fix NULL dereference of tsm_ops
  coco/guest: Move shared guest CC infrastructure to drivers/virt/coco/guest/
  configfs-tsm: Namespace TSM report symbols
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86_sev_for_v6.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2025-05-27T17:21:04+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-05-27T17:21:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=dd3922cf9d4d1421e5883614d1a6add912131c00'/>
<id>dd3922cf9d4d1421e5883614d1a6add912131c00</id>
<content type='text'>
Pull AMD SEV update from Borislav Petkov:
 "Add a virtual TPM driver glue which allows a guest kernel to talk to a
  TPM device emulated by a Secure VM Service Module (SVSM) - a helper
  module of sorts which runs at a different privilege level in the
  SEV-SNP VM stack.

  The intent being that a TPM device is emulated by a trusted entity and
  not by the untrusted host which is the default assumption in the
  confidential computing scenarios"

* tag 'x86_sev_for_v6.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sev: Register tpm-svsm platform device
  tpm: Add SNP SVSM vTPM driver
  svsm: Add header with SVSM_VTPM_CMD helpers
  x86/sev: Add SVSM vTPM probe/send_command functions
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull AMD SEV update from Borislav Petkov:
 "Add a virtual TPM driver glue which allows a guest kernel to talk to a
  TPM device emulated by a Secure VM Service Module (SVSM) - a helper
  module of sorts which runs at a different privilege level in the
  SEV-SNP VM stack.

  The intent being that a TPM device is emulated by a trusted entity and
  not by the untrusted host which is the default assumption in the
  confidential computing scenarios"

* tag 'x86_sev_for_v6.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sev: Register tpm-svsm platform device
  tpm: Add SNP SVSM vTPM driver
  svsm: Add header with SVSM_VTPM_CMD helpers
  x86/sev: Add SVSM vTPM probe/send_command functions
</pre>
</div>
</content>
</entry>
<entry>
<title>arch/x86: Provide the CPU number in the wakeup AP callback</title>
<updated>2025-05-23T16:30:56+00:00</updated>
<author>
<name>Roman Kisel</name>
<email>romank@linux.microsoft.com</email>
</author>
<published>2025-05-07T18:22:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=43cb39ad260a168abf6da3a48f394afff92d436b'/>
<id>43cb39ad260a168abf6da3a48f394afff92d436b</id>
<content type='text'>
When starting APs, confidential guests and paravisor guests
need to know the CPU number, and the pattern of using the linear
search has emerged in several places. With N processors that leads
to the O(N^2) time complexity.

Provide the CPU number in the AP wake up callback so that one can
get the CPU number in constant time.

Suggested-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Signed-off-by: Roman Kisel &lt;romank@linux.microsoft.com&gt;
Reviewed-by: Tom Lendacky &lt;thomas.lendacky@amd.com&gt;
Reviewed-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Link: https://lore.kernel.org/r/20250507182227.7421-3-romank@linux.microsoft.com
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
Message-ID: &lt;20250507182227.7421-3-romank@linux.microsoft.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When starting APs, confidential guests and paravisor guests
need to know the CPU number, and the pattern of using the linear
search has emerged in several places. With N processors that leads
to the O(N^2) time complexity.

Provide the CPU number in the AP wake up callback so that one can
get the CPU number in constant time.

Suggested-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Signed-off-by: Roman Kisel &lt;romank@linux.microsoft.com&gt;
Reviewed-by: Tom Lendacky &lt;thomas.lendacky@amd.com&gt;
Reviewed-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Link: https://lore.kernel.org/r/20250507182227.7421-3-romank@linux.microsoft.com
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
Message-ID: &lt;20250507182227.7421-3-romank@linux.microsoft.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'v6.15-rc7' into x86/core, to pick up fixes</title>
<updated>2025-05-21T06:45:03+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2025-05-21T06:42:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=412751aa6991501d7defeadecfede59043d1b5e8'/>
<id>412751aa6991501d7defeadecfede59043d1b5e8</id>
<content type='text'>
Pick up build fixes from upstream to make this tree more testable.

Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pick up build fixes from upstream to make this tree more testable.

Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/cpuid: Set &lt;asm/cpuid/api.h&gt; as the main CPUID header</title>
<updated>2025-05-15T16:23:55+00:00</updated>
<author>
<name>Ahmed S. Darwish</name>
<email>darwi@linutronix.de</email>
</author>
<published>2025-05-08T15:02:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=968e3000680713f712bcf02c51c4d7bb7d4d7685'/>
<id>968e3000680713f712bcf02c51c4d7bb7d4d7685</id>
<content type='text'>
The main CPUID header &lt;asm/cpuid.h&gt; was originally a storefront for the
headers:

    &lt;asm/cpuid/api.h&gt;
    &lt;asm/cpuid/leaf_0x2_api.h&gt;

Now that the latter CPUID(0x2) header has been merged into the former,
there is no practical difference between &lt;asm/cpuid.h&gt; and
&lt;asm/cpuid/api.h&gt;.

Migrate all users to the &lt;asm/cpuid/api.h&gt; header, in preparation of
the removal of &lt;asm/cpuid.h&gt;.

Don't remove &lt;asm/cpuid.h&gt; just yet, in case some new code in -next
started using it.

Suggested-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Ahmed S. Darwish &lt;darwi@linutronix.de&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: John Ogness &lt;john.ogness@linutronix.de&gt;
Cc: x86-cpuid@lists.linux.dev
Link: https://lore.kernel.org/r/20250508150240.172915-3-darwi@linutronix.de
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The main CPUID header &lt;asm/cpuid.h&gt; was originally a storefront for the
headers:

    &lt;asm/cpuid/api.h&gt;
    &lt;asm/cpuid/leaf_0x2_api.h&gt;

Now that the latter CPUID(0x2) header has been merged into the former,
there is no practical difference between &lt;asm/cpuid.h&gt; and
&lt;asm/cpuid/api.h&gt;.

Migrate all users to the &lt;asm/cpuid/api.h&gt; header, in preparation of
the removal of &lt;asm/cpuid.h&gt;.

Don't remove &lt;asm/cpuid.h&gt; just yet, in case some new code in -next
started using it.

Suggested-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Ahmed S. Darwish &lt;darwi@linutronix.de&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: John Ogness &lt;john.ogness@linutronix.de&gt;
Cc: x86-cpuid@lists.linux.dev
Link: https://lore.kernel.org/r/20250508150240.172915-3-darwi@linutronix.de
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/sev: Make sure pages are not skipped during kdump</title>
<updated>2025-05-13T17:47:48+00:00</updated>
<author>
<name>Ashish Kalra</name>
<email>ashish.kalra@amd.com</email>
</author>
<published>2025-05-06T18:35:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=82b7f88f2316c5442708daeb0b5ec5aa54c8ff7f'/>
<id>82b7f88f2316c5442708daeb0b5ec5aa54c8ff7f</id>
<content type='text'>
When shared pages are being converted to private during kdump, additional
checks are performed. They include handling the case of a GHCB page being
contained within a huge page.

Currently, this check incorrectly skips a page just below the GHCB page from
being transitioned back to private during kdump preparation.

This skipped page causes a 0x404 #VC exception when it is accessed later while
dumping guest memory for vmcore generation.

Correct the range to be checked for GHCB contained in a huge page.  Also,
ensure that the skipped huge page containing the GHCB page is transitioned
back to private by applying the correct address mask later when changing GHCBs
to private at end of kdump preparation.

  [ bp: Massage commit message. ]

Fixes: 3074152e56c9 ("x86/sev: Convert shared memory back to private on kexec")
Signed-off-by: Ashish Kalra &lt;ashish.kalra@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Tom Lendacky &lt;thomas.lendacky@amd.com&gt;
Tested-by: Srikanth Aithal &lt;sraithal@amd.com&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250506183529.289549-1-Ashish.Kalra@amd.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When shared pages are being converted to private during kdump, additional
checks are performed. They include handling the case of a GHCB page being
contained within a huge page.

Currently, this check incorrectly skips a page just below the GHCB page from
being transitioned back to private during kdump preparation.

This skipped page causes a 0x404 #VC exception when it is accessed later while
dumping guest memory for vmcore generation.

Correct the range to be checked for GHCB contained in a huge page.  Also,
ensure that the skipped huge page containing the GHCB page is transitioned
back to private by applying the correct address mask later when changing GHCBs
to private at end of kdump preparation.

  [ bp: Massage commit message. ]

Fixes: 3074152e56c9 ("x86/sev: Convert shared memory back to private on kexec")
Signed-off-by: Ashish Kalra &lt;ashish.kalra@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Tom Lendacky &lt;thomas.lendacky@amd.com&gt;
Tested-by: Srikanth Aithal &lt;sraithal@amd.com&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250506183529.289549-1-Ashish.Kalra@amd.com
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/sev: Do not touch VMSA pages during SNP guest memory kdump</title>
<updated>2025-05-13T17:40:44+00:00</updated>
<author>
<name>Ashish Kalra</name>
<email>ashish.kalra@amd.com</email>
</author>
<published>2025-04-28T21:41:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d2062cc1b1c367d5d019f595ef860159e1301351'/>
<id>d2062cc1b1c367d5d019f595ef860159e1301351</id>
<content type='text'>
When kdump is running makedumpfile to generate vmcore and dump SNP guest
memory it touches the VMSA page of the vCPU executing kdump.

It then results in unrecoverable #NPF/RMP faults as the VMSA page is
marked busy/in-use when the vCPU is running and subsequently a causes
guest softlockup/hang.

Additionally, other APs may be halted in guest mode and their VMSA pages
are marked busy and touching these VMSA pages during guest memory dump
will also cause #NPF.

Issue AP_DESTROY GHCB calls on other APs to ensure they are kicked out
of guest mode and then clear the VMSA bit on their VMSA pages.

If the vCPU running kdump is an AP, mark it's VMSA page as offline to
ensure that makedumpfile excludes that page while dumping guest memory.

Fixes: 3074152e56c9 ("x86/sev: Convert shared memory back to private on kexec")
Signed-off-by: Ashish Kalra &lt;ashish.kalra@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Pankaj Gupta &lt;pankaj.gupta@amd.com&gt;
Reviewed-by: Tom Lendacky &lt;thomas.lendacky@amd.com&gt;
Tested-by: Srikanth Aithal &lt;sraithal@amd.com&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250428214151.155464-1-Ashish.Kalra@amd.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When kdump is running makedumpfile to generate vmcore and dump SNP guest
memory it touches the VMSA page of the vCPU executing kdump.

It then results in unrecoverable #NPF/RMP faults as the VMSA page is
marked busy/in-use when the vCPU is running and subsequently a causes
guest softlockup/hang.

Additionally, other APs may be halted in guest mode and their VMSA pages
are marked busy and touching these VMSA pages during guest memory dump
will also cause #NPF.

Issue AP_DESTROY GHCB calls on other APs to ensure they are kicked out
of guest mode and then clear the VMSA bit on their VMSA pages.

If the vCPU running kdump is an AP, mark it's VMSA page as offline to
ensure that makedumpfile excludes that page while dumping guest memory.

Fixes: 3074152e56c9 ("x86/sev: Convert shared memory back to private on kexec")
Signed-off-by: Ashish Kalra &lt;ashish.kalra@amd.com&gt;
Signed-off-by: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Reviewed-by: Pankaj Gupta &lt;pankaj.gupta@amd.com&gt;
Reviewed-by: Tom Lendacky &lt;thomas.lendacky@amd.com&gt;
Tested-by: Srikanth Aithal &lt;sraithal@amd.com&gt;
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250428214151.155464-1-Ashish.Kalra@amd.com
</pre>
</div>
</content>
</entry>
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