KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-22013
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-04-08 09:15:25 UTC
Updated2026-07-30 06:22:03 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state There are several problems with the way hyp code lazily saves the host's FPSIMD/SVE state, including: * Host SVE being discarded unexpectedly due to inconsistent configuration of TIF_SVE and CPACR_ELx.ZEN. This has been seen to result in QEMU crashes where SVE is used by memmove(), as reported by Eric Auger: https://issues.redhat.com/browse/RHEL-68997 * Host SVE state is discarded *after* modification by ptrace, which was an unintentional ptrace ABI change introduced with lazy discarding of SVE state. * The host FPMR value can be discarded when running a non-protected VM, where FPMR support is not exposed to a VM, and that VM uses FPSIMD/SVE. In these cases the hyp code does not save the host's FPMR before unbinding the host's FPSIMD/SVE/SME state, leaving a stale value in memory. Avoid these by eagerly saving and "flushing" the host's FPSIMD/SVE/SME state when loading a vCPU such that KVM does not need to save any of the host's FPSIMD/SVE/SME state. For clarity, fpsimd_kvm_prepare() is removed and the necessary call to fpsimd_save_and_flush_cpu_state() is placed in kvm_arch_vcpu_load_fp(). As 'fpsimd_state' and 'fpmr_ptr' should not be used, they are set to NULL; all uses of these will be removed in subsequent patches. Historical problems go back at least as far as v5.17, e.g. erroneous assumptions about TIF_SVE being clear in commit: 8383741ab2e773a9 ("KVM: arm64: Get rid of host SVE tracking/saving") ... and so this eager save+flush probably needs to be backported to ALL stable trees.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: NVD-CWE-noinfo

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.3HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
3.1CNADECLARED7.3HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected c4ab60a86c5ed7c0d727c6dc8cec352e16bc7f90 5289ac43b69c61a49c75720921f2008005a31c43 git Not specified
CNA Linux Linux affected d5f7d3833b534f9e43e548461dba1e60aa82f587 04c50cc23a492c4d43fdaefc7c1ecc0ff6f7b82e git Not specified
CNA Linux Linux affected 93ae6b01bafee8fa385aa25ee7ebdb40057f6abe 806d5c1e1d2e5502175a24bf70f251648d99c36a git Not specified
CNA Linux Linux affected 93ae6b01bafee8fa385aa25ee7ebdb40057f6abe 79e140bba70bcacc5fe15bf8c0b958793fd7d56f git Not specified
CNA Linux Linux affected 93ae6b01bafee8fa385aa25ee7ebdb40057f6abe 900b444be493b7f404898c785d6605b177a093d0 git Not specified
CNA Linux Linux affected 93ae6b01bafee8fa385aa25ee7ebdb40057f6abe fbc7e61195e23f744814e78524b73b59faa54ab4 git Not specified
CNA Linux Linux affected 6.2 Not specified
CNA Linux Linux unaffected 6.2 semver Not specified
CNA Linux Linux unaffected 6.6.85 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.21 6.12.* semver Not specified
CNA Linux Linux unaffected 6.13.9 6.13.* semver Not specified
CNA Linux Linux unaffected 6.14 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/79e140bba70bcacc5fe15bf8c0b958793fd7d56f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/fbc7e61195e23f744814e78524b73b59faa54ab4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/5289ac43b69c61a49c75720921f2008005a31c43 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/806d5c1e1d2e5502175a24bf70f251648d99c36a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/04c50cc23a492c4d43fdaefc7c1ecc0ff6f7b82e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/900b444be493b7f404898c785d6605b177a093d0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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