CVE-2026-64310

In the Linux kernel, the following vulnerability has been resolved:

crypto: ccp - Do not initialize SNP for SEV ioctls

Sashiko notes:

> if SEV initialization fails and KVM is actively running normal VMs, could a

> userspace process trigger this code path via /dev/sev ioctls (e.g.,

> SEV_PDH_GEN) and zero out MSR_VM_HSAVE_PA globally? Would the next VMRUN

> execution for an active VM trigger a general protection fault and crash the

> host?

sev_move_to_init_state() is called for ioctls requiring only SEV firmware:

SEV_PEK_GEN, SEV_PDH_GEN, SEV_PEK_CSR, SEV_PEK_CERT_IMPORT, and

SEV_PDH_CERT_EXPORT. After the firmware command, it does SEV_SHUTDOWN on

the SEV firmware. Since these commands do not require SNP to be

initialized, skip it by calling __sev_platform_init_locked() which only

initializes the SEV firmware. This way SNP is not Initialized at all, and

HSAVE_PA is not cleared.

The previous code saved any SEV initialization firmware error to

init_args.error and then threw it away and hardcoded the return value of

INVALID_PLATFORM_STATE regardless of the real firmware error. This patch

changes it to surface the underlying error, which is hopefully both more

useful and doesn't cause any problems.

Note that it is still safe to call __sev_firmware_shutdown() directly: it

calls __sev_snp_shutdown_locked(), which skips SNP shutdown if SNP was not

initialized.