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Suravee Suthikulpanit f33b678543 KVM: SVM: Disable AVIC on SNP-enabled system without HvInUseWrAllowed feature 
commit d81cadbe16 upstream.

On SNP-enabled system, VMRUN marks AVIC Backing Page as in-use while
the guest is running for both secure and non-secure guest. Any hypervisor
write to the in-use vCPU's AVIC backing page (e.g. to inject an interrupt)
will generate unexpected #PF in the host.

Currently, attempt to run AVIC guest would result in the following error:

    BUG: unable to handle page fault for address: ff3a442e549cc270
    #PF: supervisor write access in kernel mode
    #PF: error_code(0x80000003) - RMP violation
    PGD b6ee01067 P4D b6ee02067 PUD 10096d063 PMD 11c540063 PTE 80000001149cc163
    SEV-SNP: PFN 0x1149cc unassigned, dumping non-zero entries in 2M PFN region: [0x114800 - 0x114a00]
    ...

Newer AMD system is enhanced to allow hypervisor to modify the backing page
for non-secure guest on SNP-enabled system. This enhancement is available
when the CPUID Fn8000_001F_EAX bit 30 is set (HvInUseWrAllowed).

This table describes AVIC support matrix w.r.t. SNP enablement:

               | Non-SNP system |     SNP system
-----------------------------------------------------
 Non-SNP guest |  AVIC Activate | AVIC Activate iff
               |                | HvInuseWrAllowed=1
-----------------------------------------------------
     SNP guest |      N/A       |    Secure AVIC

Therefore, check and disable AVIC in kvm_amd driver when the feature is not
available on SNP-enabled system.

See the AMD64 Architecture Programmer’s Manual (APM) Volume 2 for detail.
(https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/
programmer-references/40332.pdf)

Fixes: 216d106c7f ("x86/sev: Add SEV-SNP host initialization support")
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20241104075845.7583-1-suravee.suthikulpanit@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Cc: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-05-02 07:59:05 +02:00
arch KVM: SVM: Disable AVIC on SNP-enabled system without HvInUseWrAllowed feature 2025-05-02 07:59:05 +02:00
block block: never reduce ra_pages in blk_apply_bdi_limits 2025-05-02 07:59:03 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: api - Fix larval relookup type and mask 2025-04-10 14:39:20 +02:00
Documentation bpf: Add namespace to BPF internal symbols 2025-05-02 07:59:04 +02:00
drivers iommu/amd: Return an error if vCPU affinity is set for non-vCPU IRTE 2025-05-02 07:59:03 +02:00
fs splice: remove duplicate noinline from pipe_clear_nowait 2025-05-02 07:59:04 +02:00
include drm/xe/bmg: Add one additional PCI ID 2025-05-02 07:58:58 +02:00
init ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE 2025-04-10 14:39:40 +02:00
io_uring block: add a rq_list type 2025-04-25 10:48:06 +02:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel bpf: Add namespace to BPF internal symbols 2025-05-02 07:59:04 +02:00
lib lib/Kconfig.ubsan: Remove 'default UBSAN' from UBSAN_INTEGER_WRAP 2025-05-02 07:58:58 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/vmscan: don't try to reclaim hwpoison folio 2025-05-02 07:58:52 +02:00
net net_sched: hfsc: Fix a potential UAF in hfsc_dequeue() too 2025-05-02 07:59:02 +02:00
rust rust: Fix enabling Rust and building with GCC for LoongArch 2025-04-10 14:39:36 +02:00
samples tracing: Verify event formats that have "%*p.." 2025-05-02 07:58:52 +02:00
scripts scripts: generate_rust_analyzer: Add ffi crate 2025-04-25 10:48:04 +02:00
security landlock: Prepare to add second errata 2025-04-20 10:15:56 +02:00
sound ASoC: qcom: Fix sc7280 lpass potential buffer overflow 2025-04-25 10:47:50 +02:00
tools selftests/bpf: extend changes_pkt_data with cases w/o subprograms 2025-04-25 10:48:08 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: Allow building irqbypass.ko as as module when kvm.ko is a module 2025-04-20 10:15:54 +02:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: enable Clippy's check-private-items 2025-03-13 13:01:42 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: add entry for the Rust alloc module 2025-03-13 13:01:47 +01:00
Makefile Linux 6.12.25 2025-04-25 10:48:08 +02:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.