diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index c653b8eeb2..ca7904ac2c 100644 --- a/include/hw/i386/pc.h +++ b/include/hw/i386/pc.h @@ -172,6 +172,8 @@ typedef enum { SEV_DESC_TYPE_SNP_SECRETS, /* The section contains address that can be used as a CPUID page */ SEV_DESC_TYPE_CPUID, + /* The section contains the region for kernel hashes for measured direct boot */ + SEV_DESC_TYPE_SNP_KERNEL_HASHES = 0x10, } ovmf_sev_metadata_desc_type; diff --git a/target/i386/sev.c b/target/i386/sev.c index 3fce4c08eb..004c667ac1 100644 --- a/target/i386/sev.c +++ b/target/i386/sev.c @@ -115,6 +115,10 @@ struct SevCommonStateClass { X86ConfidentialGuestClass parent_class; /* public */ + bool (*build_kernel_loader_hashes)(SevCommonState *sev_common, + SevHashTableDescriptor *area, + SevKernelLoaderContext *ctx, + Error **errp); int (*launch_start)(SevCommonState *sev_common); void (*launch_finish)(SevCommonState *sev_common); int (*launch_update_data)(SevCommonState *sev_common, hwaddr gpa, uint8_t *ptr, uint64_t len); @@ -154,6 +158,9 @@ struct SevSnpGuestState { struct kvm_sev_snp_launch_start kvm_start_conf; struct kvm_sev_snp_launch_finish kvm_finish_conf; + + uint32_t kernel_hashes_offset; + PaddedSevHashTable *kernel_hashes_data; }; #define DEFAULT_GUEST_POLICY 0x1 /* disable debug */ @@ -1189,6 +1196,23 @@ snp_launch_update_cpuid(uint32_t cpuid_addr, void *hva, uint32_t cpuid_len) KVM_SEV_SNP_PAGE_TYPE_CPUID); } +static int +snp_launch_update_kernel_hashes(SevSnpGuestState *sev_snp, uint32_t addr, + void *hva, uint32_t len) +{ + int type = KVM_SEV_SNP_PAGE_TYPE_ZERO; + if (sev_snp->parent_obj.kernel_hashes) { + assert(sev_snp->kernel_hashes_data); + assert((sev_snp->kernel_hashes_offset + + sizeof(*sev_snp->kernel_hashes_data)) <= len); + memset(hva, 0, len); + memcpy(hva + sev_snp->kernel_hashes_offset, sev_snp->kernel_hashes_data, + sizeof(*sev_snp->kernel_hashes_data)); + type = KVM_SEV_SNP_PAGE_TYPE_NORMAL; + } + return snp_launch_update_data(addr, hva, len, type); +} + static int snp_metadata_desc_to_page_type(int desc_type) { @@ -1225,6 +1249,9 @@ snp_populate_metadata_pages(SevSnpGuestState *sev_snp, if (type == KVM_SEV_SNP_PAGE_TYPE_CPUID) { ret = snp_launch_update_cpuid(desc->base, hva, desc->len); + } else if (desc->type == SEV_DESC_TYPE_SNP_KERNEL_HASHES) { + ret = snp_launch_update_kernel_hashes(sev_snp, desc->base, hva, + desc->len); } else { ret = snp_launch_update_data(desc->base, hva, desc->len, type); } @@ -1823,40 +1850,31 @@ static bool build_kernel_loader_hashes(PaddedSevHashTable *padded_ht, return true; } -/* - * Add the hashes of the linux kernel/initrd/cmdline to an encrypted guest page - * which is included in SEV's initial memory measurement. - */ -bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp) +static bool sev_snp_build_kernel_loader_hashes(SevCommonState *sev_common, + SevHashTableDescriptor *area, + SevKernelLoaderContext *ctx, + Error **errp) +{ + /* + * SNP: Populate the hashes table in an area that later in + * snp_launch_update_kernel_hashes() will be copied to the guest memory + * and encrypted. + */ + SevSnpGuestState *sev_snp_guest = SEV_SNP_GUEST(sev_common); + sev_snp_guest->kernel_hashes_offset = area->base & ~TARGET_PAGE_MASK; + sev_snp_guest->kernel_hashes_data = g_new0(PaddedSevHashTable, 1); + return build_kernel_loader_hashes(sev_snp_guest->kernel_hashes_data, ctx, errp); +} + +static bool sev_build_kernel_loader_hashes(SevCommonState *sev_common, + SevHashTableDescriptor *area, + SevKernelLoaderContext *ctx, + Error **errp) { - uint8_t *data; - SevHashTableDescriptor *area; PaddedSevHashTable *padded_ht; hwaddr mapped_len = sizeof(*padded_ht); MemTxAttrs attrs = { 0 }; bool ret = true; - SevCommonState *sev_common = SEV_COMMON(MACHINE(qdev_get_machine())->cgs); - - /* - * Only add the kernel hashes if the sev-guest configuration explicitly - * stated kernel-hashes=on. - */ - if (!sev_common->kernel_hashes) { - return false; - } - - if (!pc_system_ovmf_table_find(SEV_HASH_TABLE_RV_GUID, &data, NULL)) { - error_setg(errp, "SEV: kernel specified but guest firmware " - "has no hashes table GUID"); - return false; - } - - area = (SevHashTableDescriptor *)data; - if (!area->base || area->size < sizeof(PaddedSevHashTable)) { - error_setg(errp, "SEV: guest firmware hashes table area is invalid " - "(base=0x%x size=0x%x)", area->base, area->size); - return false; - } /* * Populate the hashes table in the guest's memory at the OVMF-designated @@ -1884,6 +1902,41 @@ bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp) return ret; } +/* + * Add the hashes of the linux kernel/initrd/cmdline to an encrypted guest page + * which is included in SEV's initial memory measurement. + */ +bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp) +{ + uint8_t *data; + SevHashTableDescriptor *area; + SevCommonState *sev_common = SEV_COMMON(MACHINE(qdev_get_machine())->cgs); + SevCommonStateClass *klass = SEV_COMMON_GET_CLASS(sev_common); + + /* + * Only add the kernel hashes if the sev-guest configuration explicitly + * stated kernel-hashes=on. + */ + if (!sev_common->kernel_hashes) { + return false; + } + + if (!pc_system_ovmf_table_find(SEV_HASH_TABLE_RV_GUID, &data, NULL)) { + error_setg(errp, "SEV: kernel specified but guest firmware " + "has no hashes table GUID"); + return false; + } + + area = (SevHashTableDescriptor *)data; + if (!area->base || area->size < sizeof(PaddedSevHashTable)) { + error_setg(errp, "SEV: guest firmware hashes table area is invalid " + "(base=0x%x size=0x%x)", area->base, area->size); + return false; + } + + return klass->build_kernel_loader_hashes(sev_common, area, ctx, errp); +} + static char * sev_common_get_sev_device(Object *obj, Error **errp) { @@ -1998,6 +2051,7 @@ sev_guest_class_init(ObjectClass *oc, void *data) SevCommonStateClass *klass = SEV_COMMON_CLASS(oc); X86ConfidentialGuestClass *x86_klass = X86_CONFIDENTIAL_GUEST_CLASS(oc); + klass->build_kernel_loader_hashes = sev_build_kernel_loader_hashes; klass->launch_start = sev_launch_start; klass->launch_finish = sev_launch_finish; klass->launch_update_data = sev_launch_update_data; @@ -2242,6 +2296,7 @@ sev_snp_guest_class_init(ObjectClass *oc, void *data) SevCommonStateClass *klass = SEV_COMMON_CLASS(oc); X86ConfidentialGuestClass *x86_klass = X86_CONFIDENTIAL_GUEST_CLASS(oc); + klass->build_kernel_loader_hashes = sev_snp_build_kernel_loader_hashes; klass->launch_start = sev_snp_launch_start; klass->launch_finish = sev_snp_launch_finish; klass->launch_update_data = sev_snp_launch_update_data;