In 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.
Advisories
Source ID Title
EUVD EUVD EUVD-2025-10342 In 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.
Ubuntu USN Ubuntu USN USN-7605-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7605-2 Linux kernel (Low Latency) vulnerabilities
Ubuntu USN Ubuntu USN USN-7606-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-7628-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7764-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7764-2 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7765-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-7766-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7767-1 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7767-2 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7779-1 Linux kernel (IBM) vulnerabilities
Ubuntu USN Ubuntu USN USN-7790-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-7800-1 Linux kernel (Raspberry Pi Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7801-1 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7802-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7801-2 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-7809-1 Linux kernel (Azure, N-Series) vulnerabilities
Ubuntu USN Ubuntu USN USN-7801-3 Linux kernel (Oracle) vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 28 Oct 2025 17:30:00 +0000

Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*

Fri, 02 May 2025 06:30:00 +0000


Fri, 25 Apr 2025 10:30:00 +0000


Wed, 09 Apr 2025 15:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-99
Metrics threat_severity

Low

threat_severity

Moderate


Wed, 09 Apr 2025 02:00:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low


Tue, 08 Apr 2025 08:30:00 +0000

Type Values Removed Values Added
Description In 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.
Title KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-05-04T07:27:37.103Z

Reserved: 2024-12-29T08:45:45.806Z

Link: CVE-2025-22013

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2025-04-08T09:15:25.643

Modified: 2025-10-28T17:16:03.533

Link: CVE-2025-22013

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-04-08T00:00:00Z

Links: CVE-2025-22013 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-06-23T09:16:29Z