diff options
| author | Tycho Andersen (AMD) <tycho@kernel.org> | 2026-03-24 10:13:00 -0600 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2026-03-30 12:02:12 +0200 |
| commit | f995fc377ac7d3757e1d94e6403940c4b8f3d76e (patch) | |
| tree | a4e55da32799e29c828e21f1b829cb4e373b316a /drivers/crypto | |
| parent | 7b2bc5f0ab983a7aad7fa5180cede4b3e91fc164 (diff) | |
crypto/ccp: Implement SNP x86 shutdown
The SEV firmware has support to disable SNP during an SNP_SHUTDOWN_EX command.
Verify that this support is available and set the flag so that SNP is disabled
when it is not being used.
In cases where SNP is disabled, skip the call to amd_iommu_snp_disable(), as
all of the IOMMU pages have already been made shared. Also skip the panic
case, since snp_shutdown() does IPIs.
Signed-off-by: Tycho Andersen (AMD) <tycho@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Link: https://patch.msgid.link/20260324161301.1353976-7-tycho@kernel.org
Diffstat (limited to 'drivers/crypto')
| -rw-r--r-- | drivers/crypto/ccp/sev-dev.c | 41 |
1 files changed, 24 insertions, 17 deletions
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 0d0c09a3a0af..cc5c5b3ad66d 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -2039,6 +2039,8 @@ static int __sev_snp_shutdown_locked(int *error, bool panic) memset(&data, 0, sizeof(data)); data.len = sizeof(data); data.iommu_snp_shutdown = 1; + if (sev->snp_feat_info_0.ecx & SNP_X86_SHUTDOWN_SUPPORTED) + data.x86_snp_shutdown = 1; /* * If invoked during panic handling, local interrupts are disabled @@ -2072,23 +2074,28 @@ static int __sev_snp_shutdown_locked(int *error, bool panic) return ret; } - /* - * SNP_SHUTDOWN_EX with IOMMU_SNP_SHUTDOWN set to 1 disables SNP - * enforcement by the IOMMU and also transitions all pages - * associated with the IOMMU to the Reclaim state. - * Firmware was transitioning the IOMMU pages to Hypervisor state - * before version 1.53. But, accounting for the number of assigned - * 4kB pages in a 2M page was done incorrectly by not transitioning - * to the Reclaim state. This resulted in RMP #PF when later accessing - * the 2M page containing those pages during kexec boot. Hence, the - * firmware now transitions these pages to Reclaim state and hypervisor - * needs to transition these pages to shared state. SNP Firmware - * version 1.53 and above are needed for kexec boot. - */ - ret = amd_iommu_snp_disable(); - if (ret) { - dev_err(sev->dev, "SNP IOMMU shutdown failed\n"); - return ret; + if (data.x86_snp_shutdown) { + if (!panic) + snp_shutdown(); + } else { + /* + * SNP_SHUTDOWN_EX with IOMMU_SNP_SHUTDOWN set to 1 disables SNP + * enforcement by the IOMMU and also transitions all pages + * associated with the IOMMU to the Reclaim state. + * Firmware was transitioning the IOMMU pages to Hypervisor state + * before version 1.53. But, accounting for the number of assigned + * 4kB pages in a 2M page was done incorrectly by not transitioning + * to the Reclaim state. This resulted in RMP #PF when later accessing + * the 2M page containing those pages during kexec boot. Hence, the + * firmware now transitions these pages to Reclaim state and hypervisor + * needs to transition these pages to shared state. SNP Firmware + * version 1.53 and above are needed for kexec boot. + */ + ret = amd_iommu_snp_disable(); + if (ret) { + dev_err(sev->dev, "SNP IOMMU shutdown failed\n"); + return ret; + } } snp_leak_hv_fixed_pages(); |