diff options
| author | Tycho Andersen (AMD) <tycho@kernel.org> | 2026-05-04 19:51:45 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2026-05-15 13:08:37 +0300 |
| commit | 5a1364da2f04217a36e2fdfa2db4ee025b383a20 (patch) | |
| tree | a5e4934b74983f77a421e2907d61b51631d6a50b | |
| parent | fb1758e74b8061aacfbce7bbb7a7cc650537e167 (diff) | |
| download | linux-5a1364da2f04217a36e2fdfa2db4ee025b383a20.tar.xz | |
crypto: ccp - Do not initialize SNP for ioctl(SNP_COMMIT)
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?
The SNP_COMMIT command does not require the firmware to be in any
particular state. Skip initializing it if it was previously uninitialized.
The SEV-SNP firmware specification doc 56860 does not mention SNP_COMMIT in
Table 5 as a command that is allowed in the UNINIT state, but it is in fact
allowed and a future documentation update will reflect that.
Fixes: ceac7fb89e8d ("crypto: ccp - Ensure implicit SEV/SNP init and shutdown in ioctls")
Reported-by: Sashiko
Assisted-by: Gemini:gemini-3.1-pro-preview
Link: https://sashiko.dev/#/patchset/20260324161301.1353976-1-tycho%40kernel.org
CC: <stable@vger.kernel.org>
Signed-off-by: Tycho Andersen (AMD) <tycho@kernel.org>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
| -rw-r--r-- | drivers/crypto/ccp/sev-dev.c | 13 |
1 files changed, 1 insertions, 12 deletions
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 46c5d7ee7955..de472f0503cb 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -2440,24 +2440,13 @@ cleanup: static int sev_ioctl_do_snp_commit(struct sev_issue_cmd *argp) { - struct sev_device *sev = psp_master->sev_data; struct sev_data_snp_commit buf; - bool shutdown_required = false; - int ret, error; - - if (!sev->snp_initialized) { - ret = snp_move_to_init_state(argp, &shutdown_required); - if (ret) - return ret; - } + int ret; buf.len = sizeof(buf); ret = __sev_do_cmd_locked(SEV_CMD_SNP_COMMIT, &buf, &argp->error); - if (shutdown_required) - __sev_snp_shutdown_locked(&error, false); - return ret; } |