Re: [PATCH v4 6/7] KVM: SVM: Add support to initialize SEV/SNP functionality in KVM
From: Tom Lendacky <thomas.lendacky@amd.com>
Date: 2025-02-20 19:57:44
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On 2/19/25 14:54, Ashish Kalra wrote:
From: Ashish Kalra <ashish.kalra@amd.com> Move platform initialization of SEV/SNP from PSP driver probe time to
s/PSP/CCP/
KVM module load time so that KVM can do SEV/SNP platform initialization explicitly if it actually wants to use SEV/SNP functionality. Add support for KVM to explicitly call into the PSP driver at load time
s/PSP/CCP/
to initialize SEV/SNP by default but this behavior can be altered with KVM
s/by default but this/. If required, this/
module parameters to not do SEV/SNP platform initialization at module load time if required. Additionally SEV/SNP platform shutdown is invoked during
s/if required// s/Additionally/Additionally, a corresponding/
KVM module unload time.
Some commit message comments and a minor comment below, otherwise: Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
quoted hunk ↗ jump to hunk
Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> --- arch/x86/kvm/svm/sev.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 74525651770a..213d4c15a9da 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c@@ -2933,6 +2933,7 @@ void __init sev_set_cpu_caps(void) void __init sev_hardware_setup(void) { unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count; + struct sev_platform_init_args init_args = {0}; bool sev_snp_supported = false; bool sev_es_supported = false; bool sev_supported = false;@@ -3059,6 +3060,17 @@ void __init sev_hardware_setup(void) sev_supported_vmsa_features = 0; if (sev_es_debug_swap_enabled) sev_supported_vmsa_features |= SVM_SEV_FEAT_DEBUG_SWAP; + + if (!sev_enabled) + return; + + /* + * NOTE: Always do SNP INIT regardless of sev_snp_supported + * as SNP INIT has to be done to launch legacy SEV/SEV-ES + * VMs in case SNP is enabled system-wide. + */
But won't this also do an SEV init as long as init_on_probe is true? And isn't this true for even non-SEV VMs? You have to pause all VMs before performing SNP INIT. In which case I don't see the point of this comment. I think you really just want to say: /* * Always perform SEV initialization at setup time to avoid * complications with performing SEV initialization later * (such as suspending active guests, etc.). */ Not that that is much better... but it's more accurate. Thanks, Tom
quoted hunk ↗ jump to hunk
+ init_args.probe = true; + sev_platform_init(&init_args); } void sev_hardware_unsetup(void)@@ -3074,6 +3086,9 @@ void sev_hardware_unsetup(void) misc_cg_set_capacity(MISC_CG_RES_SEV, 0); misc_cg_set_capacity(MISC_CG_RES_SEV_ES, 0); + + /* Do SEV and SNP Shutdown */ + sev_platform_shutdown(); } int sev_cpu_init(struct svm_cpu_data *sd)