| Message ID | 6d5c899030b113755e6c093e8bb9ad123280edc6.1655761627.git.ashish.kalra@amd.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) | expand |
> > +19. KVM_SNP_LAUNCH_START > +------------------------ > + > +The KVM_SNP_LAUNCH_START command is used for creating the memory encryption > +context for the SEV-SNP guest. To create the encryption context, user must > +provide a guest policy, migration agent (if any) and guest OS visible > +workarounds value as defined SEV-SNP specification. > + > +Parameters (in): struct kvm_snp_launch_start > + > +Returns: 0 on success, -negative on error > + > +:: > + > + struct kvm_sev_snp_launch_start { > + __u64 policy; /* Guest policy to use. */ > + __u64 ma_uaddr; /* userspace address of migration agent */ > + __u8 ma_en; /* 1 if the migtation agent is enabled */ migration > + __u8 imi_en; /* set IMI to 1. */ > + __u8 gosvw[16]; /* guest OS visible workarounds */ > + }; > + > +See the SEV-SNP specification for further detail on the launch input. > + > References > ========== > > > +static int snp_decommission_context(struct kvm *kvm) > +{ > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > + struct sev_data_snp_decommission data = {}; > + int ret; > + > + /* If context is not created then do nothing */ > + if (!sev->snp_context) > + return 0; > + > + data.gctx_paddr = __sme_pa(sev->snp_context); > + ret = snp_guest_decommission(&data, NULL); Do we have a similar race like in sev_unbind_asid() with DEACTIVATE and WBINVD/DF_FLUSH? The SNP_DECOMMISSION spec looks quite similar to DEACTIVATE. > + if (WARN_ONCE(ret, "failed to release guest context")) > + return ret; > + > + /* free the context page now */ > + snp_free_firmware_page(sev->snp_context); > + sev->snp_context = NULL; > + > + return 0; > +} > + > void sev_vm_destroy(struct kvm *kvm) > { > struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
[AMD Official Use Only - General] >> +static int snp_decommission_context(struct kvm *kvm) { >> + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; >> + struct sev_data_snp_decommission data = {}; >> + int ret; >> + >> + /* If context is not created then do nothing */ >> + if (!sev->snp_context) >> + return 0; >> + >> + data.gctx_paddr = __sme_pa(sev->snp_context); >> + ret = snp_guest_decommission(&data, NULL); >Do we have a similar race like in sev_unbind_asid() with DEACTIVATE and WBINVD/DF_FLUSH? The SNP_DECOMMISSION spec looks quite similar to DEACTIVATE. Yes, SNP_DECOMMISION also marks the ASID as invalid and require a WBINVD/DF_FLUSH before the ASID is re-used/re-cycled, so we need to prevent against DECOMMISION and ASID re-cycling happening at the same time. Can reuse the same RWSEM (sev_deactivate_lock) here too. Thanks, Ashish > + if (WARN_ONCE(ret, "failed to release guest context")) > + return ret; > + > + /* free the context page now */ > + snp_free_firmware_page(sev->snp_context); > + sev->snp_context = NULL; > + > + return 0; > +} > + > void sev_vm_destroy(struct kvm *kvm) > { > struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
On Mon, Jun 20, 2022 at 11:07:35PM +0000, Ashish Kalra wrote: > From: Brijesh Singh <brijesh.singh@amd.com> > > KVM_SEV_SNP_LAUNCH_START begins the launch process for an SEV-SNP guest. > The command initializes a cryptographic digest context used to construct > the measurement of the guest. If the guest is expected to be migrated, > the command also binds a migration agent (MA) to the guest. > > For more information see the SEV-SNP specification. > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > --- > .../virt/kvm/x86/amd-memory-encryption.rst | 24 ++++ > arch/x86/kvm/svm/sev.c | 115 +++++++++++++++++- > arch/x86/kvm/svm/svm.h | 1 + > include/uapi/linux/kvm.h | 10 ++ > 4 files changed, 147 insertions(+), 3 deletions(-) > > diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst > index 903023f524af..878711f2dca6 100644 > --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst > +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst > @@ -462,6 +462,30 @@ The flags bitmap is defined as:: > If the specified flags is not supported then return -EOPNOTSUPP, and the supported > flags are returned. > > +19. KVM_SNP_LAUNCH_START > +------------------------ > + > +The KVM_SNP_LAUNCH_START command is used for creating the memory encryption > +context for the SEV-SNP guest. To create the encryption context, user must > +provide a guest policy, migration agent (if any) and guest OS visible > +workarounds value as defined SEV-SNP specification. > + > +Parameters (in): struct kvm_snp_launch_start > + > +Returns: 0 on success, -negative on error > + > +:: > + > + struct kvm_sev_snp_launch_start { > + __u64 policy; /* Guest policy to use. */ > + __u64 ma_uaddr; /* userspace address of migration agent */ > + __u8 ma_en; /* 1 if the migtation agent is enabled */ > + __u8 imi_en; /* set IMI to 1. */ > + __u8 gosvw[16]; /* guest OS visible workarounds */ > + }; > + > +See the SEV-SNP specification for further detail on the launch input. > + > References > ========== > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 813bda7f7b55..9e6fc7a94ed7 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -21,6 +21,7 @@ > #include <asm/pkru.h> > #include <asm/trapnr.h> > #include <asm/fpu/xcr.h> > +#include <asm/sev.h> > > #include "x86.h" > #include "svm.h" > @@ -73,6 +74,8 @@ static unsigned int nr_asids; > static unsigned long *sev_asid_bitmap; > static unsigned long *sev_reclaim_asid_bitmap; > > +static int snp_decommission_context(struct kvm *kvm); > + > struct enc_region { > struct list_head list; > unsigned long npages; > @@ -98,12 +101,17 @@ static int sev_flush_asids(int min_asid, int max_asid) > down_write(&sev_deactivate_lock); > > wbinvd_on_all_cpus(); > - ret = sev_guest_df_flush(&error); > + > + if (sev_snp_enabled) > + ret = snp_guest_df_flush(&error); > + else > + ret = sev_guest_df_flush(&error); > > up_write(&sev_deactivate_lock); > > if (ret) > - pr_err("SEV: DF_FLUSH failed, ret=%d, error=%#x\n", ret, error); > + pr_err("SEV%s: DF_FLUSH failed, ret=%d, error=%#x\n", > + sev_snp_enabled ? "-SNP" : "", ret, error); > > return ret; > } > @@ -1825,6 +1833,74 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd) > return ret; > } > > +static void *snp_context_create(struct kvm *kvm, struct kvm_sev_cmd *argp) > +{ > + struct sev_data_snp_gctx_create data = {}; > + void *context; > + int rc; > + > + /* Allocate memory for context page */ Nit: this comment has very little value, if any. It's just stating the obvious. Instead, I'd add a description for the function: /* * Allocate and initialize a digest for the guest measurement. */ static void *snp_context_create(struct kvm *kvm, struct kvm_sev_cmd *argp) This would be much more helpful to get a grasp on "what I'm looking at". > + context = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT); > + if (!context) > + return NULL; > + > + 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; > + } > + > + return context; > +} > + > +static int snp_bind_asid(struct kvm *kvm, int *error) > +{ > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > + struct sev_data_snp_activate data = {0}; > + > + data.gctx_paddr = __psp_pa(sev->snp_context); > + data.asid = sev_get_asid(kvm); > + return sev_issue_cmd(kvm, SEV_CMD_SNP_ACTIVATE, &data, error); > +} > + > +static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) > +{ > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > + struct sev_data_snp_launch_start start = {0}; > + struct kvm_sev_snp_launch_start params; > + int rc; > + > + if (!sev_snp_guest(kvm)) > + return -ENOTTY; > + > + if (copy_from_user(¶ms, (void __user *)(uintptr_t)argp->data, sizeof(params))) > + return -EFAULT; > + > + sev->snp_context = snp_context_create(kvm, argp); > + if (!sev->snp_context) > + return -ENOTTY; > + > + start.gctx_paddr = __psp_pa(sev->snp_context); > + start.policy = params.policy; > + memcpy(start.gosvw, params.gosvw, sizeof(params.gosvw)); > + rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_START, &start, &argp->error); > + if (rc) > + goto e_free_context; > + > + sev->fd = argp->sev_fd; > + rc = snp_bind_asid(kvm, &argp->error); > + if (rc) > + goto e_free_context; > + > + return 0; > + > +e_free_context: > + snp_decommission_context(kvm); > + > + return rc; > +} > + > int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) > { > struct kvm_sev_cmd sev_cmd; > @@ -1915,6 +1991,9 @@ int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) > case KVM_SEV_RECEIVE_FINISH: > r = sev_receive_finish(kvm, &sev_cmd); > break; > + case KVM_SEV_SNP_LAUNCH_START: > + r = snp_launch_start(kvm, &sev_cmd); > + break; > default: > r = -EINVAL; > goto out; > @@ -2106,6 +2185,28 @@ int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd) > return ret; > } > > +static int snp_decommission_context(struct kvm *kvm) > +{ > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > + struct sev_data_snp_decommission data = {}; > + int ret; > + > + /* If context is not created then do nothing */ > + if (!sev->snp_context) > + return 0; > + > + data.gctx_paddr = __sme_pa(sev->snp_context); > + ret = snp_guest_decommission(&data, NULL); > + if (WARN_ONCE(ret, "failed to release guest context")) > + return ret; > + > + /* free the context page now */ > + snp_free_firmware_page(sev->snp_context); > + sev->snp_context = NULL; > + > + return 0; > +} > + > void sev_vm_destroy(struct kvm *kvm) > { > struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > @@ -2147,7 +2248,15 @@ void sev_vm_destroy(struct kvm *kvm) > } > } > > - sev_unbind_asid(kvm, sev->handle); > + if (sev_snp_guest(kvm)) { > + if (snp_decommission_context(kvm)) { > + WARN_ONCE(1, "Failed to free SNP guest context, leaking asid!\n"); > + return; > + } > + } else { > + sev_unbind_asid(kvm, sev->handle); > + } > + > sev_asid_free(sev); > } > > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index 2f45589ee596..71c011af098e 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -91,6 +91,7 @@ struct kvm_sev_info { > struct misc_cg *misc_cg; /* For misc cgroup accounting */ > atomic_t migration_in_progress; > u64 snp_init_flags; > + void *snp_context; /* SNP guest context page */ > }; > > struct kvm_svm { > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 0f912cefc544..0cb119d66ae5 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1812,6 +1812,7 @@ enum sev_cmd_id { > > /* SNP specific commands */ > KVM_SEV_SNP_INIT, > + KVM_SEV_SNP_LAUNCH_START, > > KVM_SEV_NR_MAX, > }; > @@ -1919,6 +1920,15 @@ struct kvm_snp_init { > __u64 flags; > }; > > +struct kvm_sev_snp_launch_start { > + __u64 policy; > + __u64 ma_uaddr; > + __u8 ma_en; > + __u8 imi_en; > + __u8 gosvw[16]; > + __u8 pad[6]; > +}; > + > #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) > #define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1) > #define KVM_DEV_ASSIGN_MASK_INTX (1 << 2) > -- > 2.25.1 > BR, Jarkko
diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst index 903023f524af..878711f2dca6 100644 --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst @@ -462,6 +462,30 @@ The flags bitmap is defined as:: If the specified flags is not supported then return -EOPNOTSUPP, and the supported flags are returned. +19. KVM_SNP_LAUNCH_START +------------------------ + +The KVM_SNP_LAUNCH_START command is used for creating the memory encryption +context for the SEV-SNP guest. To create the encryption context, user must +provide a guest policy, migration agent (if any) and guest OS visible +workarounds value as defined SEV-SNP specification. + +Parameters (in): struct kvm_snp_launch_start + +Returns: 0 on success, -negative on error + +:: + + struct kvm_sev_snp_launch_start { + __u64 policy; /* Guest policy to use. */ + __u64 ma_uaddr; /* userspace address of migration agent */ + __u8 ma_en; /* 1 if the migtation agent is enabled */ + __u8 imi_en; /* set IMI to 1. */ + __u8 gosvw[16]; /* guest OS visible workarounds */ + }; + +See the SEV-SNP specification for further detail on the launch input. + References ========== diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 813bda7f7b55..9e6fc7a94ed7 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -21,6 +21,7 @@ #include <asm/pkru.h> #include <asm/trapnr.h> #include <asm/fpu/xcr.h> +#include <asm/sev.h> #include "x86.h" #include "svm.h" @@ -73,6 +74,8 @@ static unsigned int nr_asids; static unsigned long *sev_asid_bitmap; static unsigned long *sev_reclaim_asid_bitmap; +static int snp_decommission_context(struct kvm *kvm); + struct enc_region { struct list_head list; unsigned long npages; @@ -98,12 +101,17 @@ static int sev_flush_asids(int min_asid, int max_asid) down_write(&sev_deactivate_lock); wbinvd_on_all_cpus(); - ret = sev_guest_df_flush(&error); + + if (sev_snp_enabled) + ret = snp_guest_df_flush(&error); + else + ret = sev_guest_df_flush(&error); up_write(&sev_deactivate_lock); if (ret) - pr_err("SEV: DF_FLUSH failed, ret=%d, error=%#x\n", ret, error); + pr_err("SEV%s: DF_FLUSH failed, ret=%d, error=%#x\n", + sev_snp_enabled ? "-SNP" : "", ret, error); return ret; } @@ -1825,6 +1833,74 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd) return ret; } +static void *snp_context_create(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ + struct sev_data_snp_gctx_create data = {}; + void *context; + int rc; + + /* Allocate memory for context page */ + context = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT); + if (!context) + return NULL; + + 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; + } + + return context; +} + +static int snp_bind_asid(struct kvm *kvm, int *error) +{ + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + struct sev_data_snp_activate data = {0}; + + data.gctx_paddr = __psp_pa(sev->snp_context); + data.asid = sev_get_asid(kvm); + return sev_issue_cmd(kvm, SEV_CMD_SNP_ACTIVATE, &data, error); +} + +static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + struct sev_data_snp_launch_start start = {0}; + struct kvm_sev_snp_launch_start params; + int rc; + + if (!sev_snp_guest(kvm)) + return -ENOTTY; + + if (copy_from_user(¶ms, (void __user *)(uintptr_t)argp->data, sizeof(params))) + return -EFAULT; + + sev->snp_context = snp_context_create(kvm, argp); + if (!sev->snp_context) + return -ENOTTY; + + start.gctx_paddr = __psp_pa(sev->snp_context); + start.policy = params.policy; + memcpy(start.gosvw, params.gosvw, sizeof(params.gosvw)); + rc = __sev_issue_cmd(argp->sev_fd, SEV_CMD_SNP_LAUNCH_START, &start, &argp->error); + if (rc) + goto e_free_context; + + sev->fd = argp->sev_fd; + rc = snp_bind_asid(kvm, &argp->error); + if (rc) + goto e_free_context; + + return 0; + +e_free_context: + snp_decommission_context(kvm); + + return rc; +} + int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) { struct kvm_sev_cmd sev_cmd; @@ -1915,6 +1991,9 @@ int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp) case KVM_SEV_RECEIVE_FINISH: r = sev_receive_finish(kvm, &sev_cmd); break; + case KVM_SEV_SNP_LAUNCH_START: + r = snp_launch_start(kvm, &sev_cmd); + break; default: r = -EINVAL; goto out; @@ -2106,6 +2185,28 @@ int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd) return ret; } +static int snp_decommission_context(struct kvm *kvm) +{ + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; + struct sev_data_snp_decommission data = {}; + int ret; + + /* If context is not created then do nothing */ + if (!sev->snp_context) + return 0; + + data.gctx_paddr = __sme_pa(sev->snp_context); + ret = snp_guest_decommission(&data, NULL); + if (WARN_ONCE(ret, "failed to release guest context")) + return ret; + + /* free the context page now */ + snp_free_firmware_page(sev->snp_context); + sev->snp_context = NULL; + + return 0; +} + void sev_vm_destroy(struct kvm *kvm) { struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; @@ -2147,7 +2248,15 @@ void sev_vm_destroy(struct kvm *kvm) } } - sev_unbind_asid(kvm, sev->handle); + if (sev_snp_guest(kvm)) { + if (snp_decommission_context(kvm)) { + WARN_ONCE(1, "Failed to free SNP guest context, leaking asid!\n"); + return; + } + } else { + sev_unbind_asid(kvm, sev->handle); + } + sev_asid_free(sev); } diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 2f45589ee596..71c011af098e 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -91,6 +91,7 @@ struct kvm_sev_info { struct misc_cg *misc_cg; /* For misc cgroup accounting */ atomic_t migration_in_progress; u64 snp_init_flags; + void *snp_context; /* SNP guest context page */ }; struct kvm_svm { diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 0f912cefc544..0cb119d66ae5 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1812,6 +1812,7 @@ enum sev_cmd_id { /* SNP specific commands */ KVM_SEV_SNP_INIT, + KVM_SEV_SNP_LAUNCH_START, KVM_SEV_NR_MAX, }; @@ -1919,6 +1920,15 @@ struct kvm_snp_init { __u64 flags; }; +struct kvm_sev_snp_launch_start { + __u64 policy; + __u64 ma_uaddr; + __u8 ma_en; + __u8 imi_en; + __u8 gosvw[16]; + __u8 pad[6]; +}; + #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) #define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1) #define KVM_DEV_ASSIGN_MASK_INTX (1 << 2)