| Message ID | 20210820155918.7518-43-brijesh.singh@amd.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support | expand |
On Fri, Aug 20, 2021 at 10:01 AM Brijesh Singh <brijesh.singh@amd.com> wrote: > > Version 2 of GHCB specification added the support for two SNP Guest > Request Message NAE events. The events allows for an SEV-SNP guest to > make request to the SEV-SNP firmware through hypervisor using the > SNP_GUEST_REQUEST API define in the SEV-SNP firmware specification. > > The SNP_EXT_GUEST_REQUEST is similar to SNP_GUEST_REQUEST with the > difference of an additional certificate blob that can be passed through > the SNP_SET_CONFIG ioctl defined in the CCP driver. The CCP driver > provides snp_guest_ext_guest_request() that is used by the KVM to get > both the report and certificate data at once. > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > --- > arch/x86/kvm/svm/sev.c | 197 +++++++++++++++++++++++++++++++++++++++-- > arch/x86/kvm/svm/svm.h | 2 + > 2 files changed, 193 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 712e8907bc39..81ccad412e55 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -19,6 +19,7 @@ > #include <linux/trace_events.h> > #include <linux/sev.h> > #include <linux/ksm.h> > +#include <linux/sev-guest.h> > #include <asm/fpu/internal.h> > > #include <asm/pkru.h> > @@ -338,6 +339,7 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) > > init_srcu_struct(&sev->psc_srcu); > ret = sev_snp_init(&argp->error); > + mutex_init(&sev->guest_req_lock); > } else { > ret = sev_platform_init(&argp->error); > } > @@ -1602,23 +1604,39 @@ static int sev_receive_finish(struct kvm *kvm, struct kvm_sev_cmd *argp) > > static void *snp_context_create(struct kvm *kvm, struct kvm_sev_cmd *argp) > { > + void *context = NULL, *certs_data = NULL, *resp_page = NULL; > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > struct sev_data_snp_gctx_create data = {}; > - void *context; > int rc; > > + /* Allocate memory used for the certs data in SNP guest request */ > + certs_data = kmalloc(SEV_FW_BLOB_MAX_SIZE, GFP_KERNEL_ACCOUNT); > + if (!certs_data) > + return NULL; > + > /* Allocate memory for context page */ > context = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT); > if (!context) > - return NULL; > + goto e_free; > + > + /* Allocate a firmware buffer used during the guest command handling. */ > + resp_page = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT); > + if (!resp_page) > + goto e_free; > > data.gctx_paddr = __psp_pa(context); > rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_GCTX_CREATE, &data, &argp->error); > - if (rc) { > - snp_free_firmware_page(context); > - return NULL; > - } > + if (rc) > + goto e_free; > + > + sev->snp_certs_data = certs_data; > > return context; > + > +e_free: > + snp_free_firmware_page(context); > + kfree(certs_data); > + return NULL; > } > > static int snp_bind_asid(struct kvm *kvm, int *error) > @@ -2248,6 +2266,8 @@ static int snp_decommission_context(struct kvm *kvm) > snp_free_firmware_page(sev->snp_context); > sev->snp_context = NULL; > > + kfree(sev->snp_certs_data); > + > return 0; > } > > @@ -2746,6 +2766,8 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm, u64 *exit_code) > case SVM_VMGEXIT_UNSUPPORTED_EVENT: > case SVM_VMGEXIT_HV_FEATURES: > case SVM_VMGEXIT_PSC: > + case SVM_VMGEXIT_GUEST_REQUEST: > + case SVM_VMGEXIT_EXT_GUEST_REQUEST: > break; > default: > goto vmgexit_err; > @@ -3161,6 +3183,155 @@ static unsigned long snp_handle_page_state_change(struct vcpu_svm *svm) > return rc ? map_to_psc_vmgexit_code(rc) : 0; > } > > +static unsigned long snp_setup_guest_buf(struct vcpu_svm *svm, > + struct sev_data_snp_guest_request *data, > + gpa_t req_gpa, gpa_t resp_gpa) > +{ > + struct kvm_vcpu *vcpu = &svm->vcpu; > + struct kvm *kvm = vcpu->kvm; > + kvm_pfn_t req_pfn, resp_pfn; > + struct kvm_sev_info *sev; > + > + sev = &to_kvm_svm(kvm)->sev_info; > + > + if (!IS_ALIGNED(req_gpa, PAGE_SIZE) || !IS_ALIGNED(resp_gpa, PAGE_SIZE)) > + return SEV_RET_INVALID_PARAM; > + > + req_pfn = gfn_to_pfn(kvm, gpa_to_gfn(req_gpa)); > + if (is_error_noslot_pfn(req_pfn)) > + return SEV_RET_INVALID_ADDRESS; > + > + resp_pfn = gfn_to_pfn(kvm, gpa_to_gfn(resp_gpa)); > + if (is_error_noslot_pfn(resp_pfn)) > + return SEV_RET_INVALID_ADDRESS; > + > + if (rmp_make_private(resp_pfn, 0, PG_LEVEL_4K, 0, true)) > + return SEV_RET_INVALID_ADDRESS; > + > + data->gctx_paddr = __psp_pa(sev->snp_context); > + data->req_paddr = __sme_set(req_pfn << PAGE_SHIFT); > + data->res_paddr = __sme_set(resp_pfn << PAGE_SHIFT); > + > + return 0; > +} > + > +static void snp_cleanup_guest_buf(struct sev_data_snp_guest_request *data, unsigned long *rc) > +{ > + u64 pfn = __sme_clr(data->res_paddr) >> PAGE_SHIFT; > + int ret; > + > + ret = snp_page_reclaim(pfn); > + if (ret) > + *rc = SEV_RET_INVALID_ADDRESS; > + > + ret = rmp_make_shared(pfn, PG_LEVEL_4K); > + if (ret) > + *rc = SEV_RET_INVALID_ADDRESS; > +} > + > +static void snp_handle_guest_request(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa) > +{ > + struct sev_data_snp_guest_request data = {0}; > + struct kvm_vcpu *vcpu = &svm->vcpu; > + struct kvm *kvm = vcpu->kvm; > + struct kvm_sev_info *sev; > + unsigned long rc; > + int err; > + > + if (!sev_snp_guest(vcpu->kvm)) { > + rc = SEV_RET_INVALID_GUEST; > + goto e_fail; > + } > + > + sev = &to_kvm_svm(kvm)->sev_info; > + > + mutex_lock(&sev->guest_req_lock); > + > + rc = snp_setup_guest_buf(svm, &data, req_gpa, resp_gpa); > + if (rc) > + goto unlock; > + > + rc = sev_issue_cmd(kvm, SEV_CMD_SNP_GUEST_REQUEST, &data, &err); > + if (rc) > + /* use the firmware error code */ > + rc = err; > + > + snp_cleanup_guest_buf(&data, &rc); > + > +unlock: > + mutex_unlock(&sev->guest_req_lock); > + > +e_fail: > + svm_set_ghcb_sw_exit_info_2(vcpu, rc); > +} > + > +static void snp_handle_ext_guest_request(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa) > +{ > + struct sev_data_snp_guest_request req = {0}; > + struct kvm_vcpu *vcpu = &svm->vcpu; > + struct kvm *kvm = vcpu->kvm; > + unsigned long data_npages; > + struct kvm_sev_info *sev; > + unsigned long rc, err; > + u64 data_gpa; > + > + if (!sev_snp_guest(vcpu->kvm)) { > + rc = SEV_RET_INVALID_GUEST; > + goto e_fail; > + } > + > + sev = &to_kvm_svm(kvm)->sev_info; > + > + data_gpa = vcpu->arch.regs[VCPU_REGS_RAX]; > + data_npages = vcpu->arch.regs[VCPU_REGS_RBX]; > + > + if (!IS_ALIGNED(data_gpa, PAGE_SIZE)) { > + rc = SEV_RET_INVALID_ADDRESS; > + goto e_fail; > + } > + > + /* Verify that requested blob will fit in certificate buffer */ > + if ((data_npages << PAGE_SHIFT) > SEV_FW_BLOB_MAX_SIZE) { > + rc = SEV_RET_INVALID_PARAM; > + goto e_fail; > + } > + > + mutex_lock(&sev->guest_req_lock); > + > + rc = snp_setup_guest_buf(svm, &req, req_gpa, resp_gpa); > + if (rc) > + goto unlock; > + > + rc = snp_guest_ext_guest_request(&req, (unsigned long)sev->snp_certs_data, > + &data_npages, &err); > + if (rc) { > + /* > + * If buffer length is small then return the expected > + * length in rbx. > + */ > + if (err == SNP_GUEST_REQ_INVALID_LEN) > + vcpu->arch.regs[VCPU_REGS_RBX] = data_npages; > + > + /* pass the firmware error code */ > + rc = err; > + goto cleanup; > + } > + > + /* Copy the certificate blob in the guest memory */ > + if (data_npages && > + kvm_write_guest(kvm, data_gpa, sev->snp_certs_data, data_npages << PAGE_SHIFT)) > + rc = SEV_RET_INVALID_ADDRESS; > + > +cleanup: > + snp_cleanup_guest_buf(&req, &rc); > + > +unlock: > + mutex_unlock(&sev->guest_req_lock); > + > +e_fail: > + svm_set_ghcb_sw_exit_info_2(vcpu, rc); > +} > + > static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm) > { > struct vmcb_control_area *control = &svm->vmcb->control; > @@ -3404,6 +3575,20 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu) > svm_set_ghcb_sw_exit_info_2(vcpu, rc); > break; > } > + case SVM_VMGEXIT_GUEST_REQUEST: { > + snp_handle_guest_request(svm, control->exit_info_1, control->exit_info_2); > + > + ret = 1; > + break; > + } > + case SVM_VMGEXIT_EXT_GUEST_REQUEST: { > + snp_handle_ext_guest_request(svm, > + control->exit_info_1, > + control->exit_info_2); > + > + ret = 1; > + break; > + } Don't we need some sort of rate limiting here? Since the PSP is a shared resource that the host needs access to as well as other guests it seems a little dangerous to let the guest spam this interface. > case SVM_VMGEXIT_UNSUPPORTED_EVENT: > vcpu_unimpl(vcpu, > "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n", > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index 280072995306..71fe46a778f3 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -92,6 +92,8 @@ struct kvm_sev_info { > u64 snp_init_flags; > void *snp_context; /* SNP guest context page */ > struct srcu_struct psc_srcu; > + void *snp_certs_data; > + struct mutex guest_req_lock; > }; > > struct kvm_svm { > -- > 2.17.1 >
On Fri, Aug 20, 2021 at 10:01 AM Brijesh Singh <brijesh.singh@amd.com> wrote: > > Version 2 of GHCB specification added the support for two SNP Guest > Request Message NAE events. The events allows for an SEV-SNP guest to > make request to the SEV-SNP firmware through hypervisor using the > SNP_GUEST_REQUEST API define in the SEV-SNP firmware specification. > > The SNP_EXT_GUEST_REQUEST is similar to SNP_GUEST_REQUEST with the > difference of an additional certificate blob that can be passed through > the SNP_SET_CONFIG ioctl defined in the CCP driver. The CCP driver > provides snp_guest_ext_guest_request() that is used by the KVM to get > both the report and certificate data at once. > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > --- > arch/x86/kvm/svm/sev.c | 197 +++++++++++++++++++++++++++++++++++++++-- > arch/x86/kvm/svm/svm.h | 2 + > 2 files changed, 193 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 712e8907bc39..81ccad412e55 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -19,6 +19,7 @@ > #include <linux/trace_events.h> > #include <linux/sev.h> > #include <linux/ksm.h> > +#include <linux/sev-guest.h> > #include <asm/fpu/internal.h> > > #include <asm/pkru.h> > @@ -338,6 +339,7 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) > > init_srcu_struct(&sev->psc_srcu); > ret = sev_snp_init(&argp->error); > + mutex_init(&sev->guest_req_lock); > } else { > ret = sev_platform_init(&argp->error); > } > @@ -1602,23 +1604,39 @@ static int sev_receive_finish(struct kvm *kvm, struct kvm_sev_cmd *argp) > > static void *snp_context_create(struct kvm *kvm, struct kvm_sev_cmd *argp) > { > + void *context = NULL, *certs_data = NULL, *resp_page = NULL; > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > struct sev_data_snp_gctx_create data = {}; > - void *context; > int rc; > > + /* Allocate memory used for the certs data in SNP guest request */ > + certs_data = kmalloc(SEV_FW_BLOB_MAX_SIZE, GFP_KERNEL_ACCOUNT); > + if (!certs_data) > + return NULL; > + > /* Allocate memory for context page */ > context = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT); > if (!context) > - return NULL; > + goto e_free; > + > + /* Allocate a firmware buffer used during the guest command handling. */ > + resp_page = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT); > + if (!resp_page) > + goto e_free; > > data.gctx_paddr = __psp_pa(context); > rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_GCTX_CREATE, &data, &argp->error); > - if (rc) { > - snp_free_firmware_page(context); > - return NULL; > - } > + if (rc) > + goto e_free; > + > + sev->snp_certs_data = certs_data; > > return context; > + > +e_free: > + snp_free_firmware_page(context); > + kfree(certs_data); > + return NULL; > } > > static int snp_bind_asid(struct kvm *kvm, int *error) > @@ -2248,6 +2266,8 @@ static int snp_decommission_context(struct kvm *kvm) > snp_free_firmware_page(sev->snp_context); > sev->snp_context = NULL; > > + kfree(sev->snp_certs_data); > + > return 0; > } > > @@ -2746,6 +2766,8 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm, u64 *exit_code) > case SVM_VMGEXIT_UNSUPPORTED_EVENT: > case SVM_VMGEXIT_HV_FEATURES: > case SVM_VMGEXIT_PSC: > + case SVM_VMGEXIT_GUEST_REQUEST: > + case SVM_VMGEXIT_EXT_GUEST_REQUEST: > break; > default: > goto vmgexit_err; > @@ -3161,6 +3183,155 @@ static unsigned long snp_handle_page_state_change(struct vcpu_svm *svm) > return rc ? map_to_psc_vmgexit_code(rc) : 0; > } > > +static unsigned long snp_setup_guest_buf(struct vcpu_svm *svm, > + struct sev_data_snp_guest_request *data, > + gpa_t req_gpa, gpa_t resp_gpa) > +{ > + struct kvm_vcpu *vcpu = &svm->vcpu; > + struct kvm *kvm = vcpu->kvm; > + kvm_pfn_t req_pfn, resp_pfn; > + struct kvm_sev_info *sev; > + > + sev = &to_kvm_svm(kvm)->sev_info; > + > + if (!IS_ALIGNED(req_gpa, PAGE_SIZE) || !IS_ALIGNED(resp_gpa, PAGE_SIZE)) > + return SEV_RET_INVALID_PARAM; > + > + req_pfn = gfn_to_pfn(kvm, gpa_to_gfn(req_gpa)); > + if (is_error_noslot_pfn(req_pfn)) > + return SEV_RET_INVALID_ADDRESS; > + > + resp_pfn = gfn_to_pfn(kvm, gpa_to_gfn(resp_gpa)); > + if (is_error_noslot_pfn(resp_pfn)) > + return SEV_RET_INVALID_ADDRESS; > + > + if (rmp_make_private(resp_pfn, 0, PG_LEVEL_4K, 0, true)) > + return SEV_RET_INVALID_ADDRESS; > + > + data->gctx_paddr = __psp_pa(sev->snp_context); > + data->req_paddr = __sme_set(req_pfn << PAGE_SHIFT); > + data->res_paddr = __sme_set(resp_pfn << PAGE_SHIFT); > + > + return 0; > +} > + > +static void snp_cleanup_guest_buf(struct sev_data_snp_guest_request *data, unsigned long *rc) > +{ > + u64 pfn = __sme_clr(data->res_paddr) >> PAGE_SHIFT; > + int ret; > + > + ret = snp_page_reclaim(pfn); > + if (ret) > + *rc = SEV_RET_INVALID_ADDRESS; > + > + ret = rmp_make_shared(pfn, PG_LEVEL_4K); > + if (ret) > + *rc = SEV_RET_INVALID_ADDRESS; > +} > + > +static void snp_handle_guest_request(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa) > +{ > + struct sev_data_snp_guest_request data = {0}; > + struct kvm_vcpu *vcpu = &svm->vcpu; > + struct kvm *kvm = vcpu->kvm; > + struct kvm_sev_info *sev; > + unsigned long rc; > + int err; > + > + if (!sev_snp_guest(vcpu->kvm)) { > + rc = SEV_RET_INVALID_GUEST; > + goto e_fail; > + } > + > + sev = &to_kvm_svm(kvm)->sev_info; > + > + mutex_lock(&sev->guest_req_lock); > + > + rc = snp_setup_guest_buf(svm, &data, req_gpa, resp_gpa); > + if (rc) > + goto unlock; > + > + rc = sev_issue_cmd(kvm, SEV_CMD_SNP_GUEST_REQUEST, &data, &err); > + if (rc) > + /* use the firmware error code */ > + rc = err; > + > + snp_cleanup_guest_buf(&data, &rc); > + > +unlock: > + mutex_unlock(&sev->guest_req_lock); > + > +e_fail: > + svm_set_ghcb_sw_exit_info_2(vcpu, rc); > +} > + > +static void snp_handle_ext_guest_request(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa) > +{ > + struct sev_data_snp_guest_request req = {0}; > + struct kvm_vcpu *vcpu = &svm->vcpu; > + struct kvm *kvm = vcpu->kvm; > + unsigned long data_npages; > + struct kvm_sev_info *sev; > + unsigned long rc, err; > + u64 data_gpa; > + > + if (!sev_snp_guest(vcpu->kvm)) { > + rc = SEV_RET_INVALID_GUEST; > + goto e_fail; > + } > + > + sev = &to_kvm_svm(kvm)->sev_info; > + > + data_gpa = vcpu->arch.regs[VCPU_REGS_RAX]; > + data_npages = vcpu->arch.regs[VCPU_REGS_RBX]; > + > + if (!IS_ALIGNED(data_gpa, PAGE_SIZE)) { > + rc = SEV_RET_INVALID_ADDRESS; > + goto e_fail; > + } > + > + /* Verify that requested blob will fit in certificate buffer */ > + if ((data_npages << PAGE_SHIFT) > SEV_FW_BLOB_MAX_SIZE) { > + rc = SEV_RET_INVALID_PARAM; > + goto e_fail; > + } > + > + mutex_lock(&sev->guest_req_lock); > + > + rc = snp_setup_guest_buf(svm, &req, req_gpa, resp_gpa); > + if (rc) > + goto unlock; > + > + rc = snp_guest_ext_guest_request(&req, (unsigned long)sev->snp_certs_data, > + &data_npages, &err); What's the point of caching the certs from the sev_device in the sev_info struct if the snp_guest_ext_guest_request() function always seems to re-copy the certs back into |sev->snp_certs_data| on every call? I am probably missing something. > + if (rc) { > + /* > + * If buffer length is small then return the expected > + * length in rbx. > + */ > + if (err == SNP_GUEST_REQ_INVALID_LEN) > + vcpu->arch.regs[VCPU_REGS_RBX] = data_npages; > + > + /* pass the firmware error code */ > + rc = err; > + goto cleanup; > + } > + > + /* Copy the certificate blob in the guest memory */ > + if (data_npages && > + kvm_write_guest(kvm, data_gpa, sev->snp_certs_data, data_npages << PAGE_SHIFT)) > + rc = SEV_RET_INVALID_ADDRESS; > + > +cleanup: > + snp_cleanup_guest_buf(&req, &rc); > + > +unlock: > + mutex_unlock(&sev->guest_req_lock); > + > +e_fail: > + svm_set_ghcb_sw_exit_info_2(vcpu, rc); > +} > + > static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm) > { > struct vmcb_control_area *control = &svm->vmcb->control; > @@ -3404,6 +3575,20 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu) > svm_set_ghcb_sw_exit_info_2(vcpu, rc); > break; > } > + case SVM_VMGEXIT_GUEST_REQUEST: { > + snp_handle_guest_request(svm, control->exit_info_1, control->exit_info_2); > + > + ret = 1; > + break; > + } > + case SVM_VMGEXIT_EXT_GUEST_REQUEST: { > + snp_handle_ext_guest_request(svm, > + control->exit_info_1, > + control->exit_info_2); > + > + ret = 1; > + break; > + } > case SVM_VMGEXIT_UNSUPPORTED_EVENT: > vcpu_unimpl(vcpu, > "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n", > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index 280072995306..71fe46a778f3 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -92,6 +92,8 @@ struct kvm_sev_info { > u64 snp_init_flags; > void *snp_context; /* SNP guest context page */ > struct srcu_struct psc_srcu; > + void *snp_certs_data; > + struct mutex guest_req_lock; > }; > > struct kvm_svm { > -- > 2.17.1 >
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 712e8907bc39..81ccad412e55 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -19,6 +19,7 @@ #include <linux/trace_events.h> #include <linux/sev.h> #include <linux/ksm.h> +#include <linux/sev-guest.h> #include <asm/fpu/internal.h> #include <asm/pkru.h> @@ -338,6 +339,7 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) init_srcu_struct(&sev->psc_srcu); ret = sev_snp_init(&argp->error); + mutex_init(&sev->guest_req_lock); } else { ret = sev_platform_init(&argp->error); } @@ -1602,23 +1604,39 @@ static int sev_receive_finish(struct kvm *kvm, struct kvm_sev_cmd *argp) static void *snp_context_create(struct kvm *kvm, struct kvm_sev_cmd *argp) { + void *context = NULL, *certs_data = NULL, *resp_page = NULL; + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; struct sev_data_snp_gctx_create data = {}; - void *context; int rc; + /* Allocate memory used for the certs data in SNP guest request */ + certs_data = kmalloc(SEV_FW_BLOB_MAX_SIZE, GFP_KERNEL_ACCOUNT); + if (!certs_data) + return NULL; + /* Allocate memory for context page */ context = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT); if (!context) - return NULL; + goto e_free; + + /* Allocate a firmware buffer used during the guest command handling. */ + resp_page = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT); + if (!resp_page) + goto e_free; data.gctx_paddr = __psp_pa(context); rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_GCTX_CREATE, &data, &argp->error); - if (rc) { - snp_free_firmware_page(context); - return NULL; - } + if (rc) + goto e_free; + + sev->snp_certs_data = certs_data; return context; + +e_free: + snp_free_firmware_page(context); + kfree(certs_data); + return NULL; } static int snp_bind_asid(struct kvm *kvm, int *error) @@ -2248,6 +2266,8 @@ static int snp_decommission_context(struct kvm *kvm) snp_free_firmware_page(sev->snp_context); sev->snp_context = NULL; + kfree(sev->snp_certs_data); + return 0; } @@ -2746,6 +2766,8 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm, u64 *exit_code) case SVM_VMGEXIT_UNSUPPORTED_EVENT: case SVM_VMGEXIT_HV_FEATURES: case SVM_VMGEXIT_PSC: + case SVM_VMGEXIT_GUEST_REQUEST: + case SVM_VMGEXIT_EXT_GUEST_REQUEST: break; default: goto vmgexit_err; @@ -3161,6 +3183,155 @@ static unsigned long snp_handle_page_state_change(struct vcpu_svm *svm) return rc ? map_to_psc_vmgexit_code(rc) : 0; } +static unsigned long snp_setup_guest_buf(struct vcpu_svm *svm, + struct sev_data_snp_guest_request *data, + gpa_t req_gpa, gpa_t resp_gpa) +{ + struct kvm_vcpu *vcpu = &svm->vcpu; + struct kvm *kvm = vcpu->kvm; + kvm_pfn_t req_pfn, resp_pfn; + struct kvm_sev_info *sev; + + sev = &to_kvm_svm(kvm)->sev_info; + + if (!IS_ALIGNED(req_gpa, PAGE_SIZE) || !IS_ALIGNED(resp_gpa, PAGE_SIZE)) + return SEV_RET_INVALID_PARAM; + + req_pfn = gfn_to_pfn(kvm, gpa_to_gfn(req_gpa)); + if (is_error_noslot_pfn(req_pfn)) + return SEV_RET_INVALID_ADDRESS; + + resp_pfn = gfn_to_pfn(kvm, gpa_to_gfn(resp_gpa)); + if (is_error_noslot_pfn(resp_pfn)) + return SEV_RET_INVALID_ADDRESS; + + if (rmp_make_private(resp_pfn, 0, PG_LEVEL_4K, 0, true)) + return SEV_RET_INVALID_ADDRESS; + + data->gctx_paddr = __psp_pa(sev->snp_context); + data->req_paddr = __sme_set(req_pfn << PAGE_SHIFT); + data->res_paddr = __sme_set(resp_pfn << PAGE_SHIFT); + + return 0; +} + +static void snp_cleanup_guest_buf(struct sev_data_snp_guest_request *data, unsigned long *rc) +{ + u64 pfn = __sme_clr(data->res_paddr) >> PAGE_SHIFT; + int ret; + + ret = snp_page_reclaim(pfn); + if (ret) + *rc = SEV_RET_INVALID_ADDRESS; + + ret = rmp_make_shared(pfn, PG_LEVEL_4K); + if (ret) + *rc = SEV_RET_INVALID_ADDRESS; +} + +static void snp_handle_guest_request(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa) +{ + struct sev_data_snp_guest_request data = {0}; + struct kvm_vcpu *vcpu = &svm->vcpu; + struct kvm *kvm = vcpu->kvm; + struct kvm_sev_info *sev; + unsigned long rc; + int err; + + if (!sev_snp_guest(vcpu->kvm)) { + rc = SEV_RET_INVALID_GUEST; + goto e_fail; + } + + sev = &to_kvm_svm(kvm)->sev_info; + + mutex_lock(&sev->guest_req_lock); + + rc = snp_setup_guest_buf(svm, &data, req_gpa, resp_gpa); + if (rc) + goto unlock; + + rc = sev_issue_cmd(kvm, SEV_CMD_SNP_GUEST_REQUEST, &data, &err); + if (rc) + /* use the firmware error code */ + rc = err; + + snp_cleanup_guest_buf(&data, &rc); + +unlock: + mutex_unlock(&sev->guest_req_lock); + +e_fail: + svm_set_ghcb_sw_exit_info_2(vcpu, rc); +} + +static void snp_handle_ext_guest_request(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t resp_gpa) +{ + struct sev_data_snp_guest_request req = {0}; + struct kvm_vcpu *vcpu = &svm->vcpu; + struct kvm *kvm = vcpu->kvm; + unsigned long data_npages; + struct kvm_sev_info *sev; + unsigned long rc, err; + u64 data_gpa; + + if (!sev_snp_guest(vcpu->kvm)) { + rc = SEV_RET_INVALID_GUEST; + goto e_fail; + } + + sev = &to_kvm_svm(kvm)->sev_info; + + data_gpa = vcpu->arch.regs[VCPU_REGS_RAX]; + data_npages = vcpu->arch.regs[VCPU_REGS_RBX]; + + if (!IS_ALIGNED(data_gpa, PAGE_SIZE)) { + rc = SEV_RET_INVALID_ADDRESS; + goto e_fail; + } + + /* Verify that requested blob will fit in certificate buffer */ + if ((data_npages << PAGE_SHIFT) > SEV_FW_BLOB_MAX_SIZE) { + rc = SEV_RET_INVALID_PARAM; + goto e_fail; + } + + mutex_lock(&sev->guest_req_lock); + + rc = snp_setup_guest_buf(svm, &req, req_gpa, resp_gpa); + if (rc) + goto unlock; + + rc = snp_guest_ext_guest_request(&req, (unsigned long)sev->snp_certs_data, + &data_npages, &err); + if (rc) { + /* + * If buffer length is small then return the expected + * length in rbx. + */ + if (err == SNP_GUEST_REQ_INVALID_LEN) + vcpu->arch.regs[VCPU_REGS_RBX] = data_npages; + + /* pass the firmware error code */ + rc = err; + goto cleanup; + } + + /* Copy the certificate blob in the guest memory */ + if (data_npages && + kvm_write_guest(kvm, data_gpa, sev->snp_certs_data, data_npages << PAGE_SHIFT)) + rc = SEV_RET_INVALID_ADDRESS; + +cleanup: + snp_cleanup_guest_buf(&req, &rc); + +unlock: + mutex_unlock(&sev->guest_req_lock); + +e_fail: + svm_set_ghcb_sw_exit_info_2(vcpu, rc); +} + static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm) { struct vmcb_control_area *control = &svm->vmcb->control; @@ -3404,6 +3575,20 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu) svm_set_ghcb_sw_exit_info_2(vcpu, rc); break; } + case SVM_VMGEXIT_GUEST_REQUEST: { + snp_handle_guest_request(svm, control->exit_info_1, control->exit_info_2); + + ret = 1; + break; + } + case SVM_VMGEXIT_EXT_GUEST_REQUEST: { + snp_handle_ext_guest_request(svm, + control->exit_info_1, + control->exit_info_2); + + ret = 1; + break; + } case SVM_VMGEXIT_UNSUPPORTED_EVENT: vcpu_unimpl(vcpu, "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n", diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 280072995306..71fe46a778f3 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -92,6 +92,8 @@ struct kvm_sev_info { u64 snp_init_flags; void *snp_context; /* SNP guest context page */ struct srcu_struct psc_srcu; + void *snp_certs_data; + struct mutex guest_req_lock; }; struct kvm_svm {
Version 2 of GHCB specification added the support for two SNP Guest Request Message NAE events. The events allows for an SEV-SNP guest to make request to the SEV-SNP firmware through hypervisor using the SNP_GUEST_REQUEST API define in the SEV-SNP firmware specification. The SNP_EXT_GUEST_REQUEST is similar to SNP_GUEST_REQUEST with the difference of an additional certificate blob that can be passed through the SNP_SET_CONFIG ioctl defined in the CCP driver. The CCP driver provides snp_guest_ext_guest_request() that is used by the KVM to get both the report and certificate data at once. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> --- arch/x86/kvm/svm/sev.c | 197 +++++++++++++++++++++++++++++++++++++++-- arch/x86/kvm/svm/svm.h | 2 + 2 files changed, 193 insertions(+), 6 deletions(-)