diff options
Diffstat (limited to 'arch/x86/kvm/svm/sev.c')
| -rw-r--r-- | arch/x86/kvm/svm/sev.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 2a36efadf9a3..dc8ccc14241d 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1262,6 +1262,9 @@ void sev_free_vcpu(struct kvm_vcpu *vcpu) if (vcpu->arch.guest_state_protected) sev_flush_guest_memory(svm, svm->vmsa, PAGE_SIZE); __free_page(virt_to_page(svm->vmsa)); + + if (svm->ghcb_sa_free) + kfree(svm->ghcb_sa); } static void dump_ghcb(struct vcpu_svm *svm) @@ -1436,6 +1439,11 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm) !ghcb_rcx_is_valid(ghcb)) goto vmgexit_err; break; + case SVM_VMGEXIT_MMIO_READ: + case SVM_VMGEXIT_MMIO_WRITE: + if (!ghcb_sw_scratch_is_valid(ghcb)) + goto vmgexit_err; + break; case SVM_VMGEXIT_UNSUPPORTED_EVENT: break; default: @@ -1470,6 +1478,24 @@ static void pre_sev_es_run(struct vcpu_svm *svm) if (!svm->ghcb) return; + if (svm->ghcb_sa_free) { + /* + * The scratch area lives outside the GHCB, so there is a + * buffer that, depending on the operation performed, may + * need to be synced, then freed. + */ + if (svm->ghcb_sa_sync) { + kvm_write_guest(svm->vcpu.kvm, + ghcb_get_sw_scratch(svm->ghcb), + svm->ghcb_sa, svm->ghcb_sa_len); + svm->ghcb_sa_sync = false; + } + + kfree(svm->ghcb_sa); + svm->ghcb_sa = NULL; + svm->ghcb_sa_free = false; + } + trace_kvm_vmgexit_exit(svm->vcpu.vcpu_id, svm->ghcb); sev_es_sync_to_ghcb(svm); @@ -1504,6 +1530,86 @@ void pre_sev_run(struct vcpu_svm *svm, int cpu) vmcb_mark_dirty(svm->vmcb, VMCB_ASID); } +#define GHCB_SCRATCH_AREA_LIMIT (16ULL * PAGE_SIZE) +static bool setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len) +{ + struct vmcb_control_area *control = &svm->vmcb->control; + struct ghcb *ghcb = svm->ghcb; + u64 ghcb_scratch_beg, ghcb_scratch_end; + u64 scratch_gpa_beg, scratch_gpa_end; + void *scratch_va; + + scratch_gpa_beg = ghcb_get_sw_scratch(ghcb); + if (!scratch_gpa_beg) { + pr_err("vmgexit: scratch gpa not provided\n"); + return false; + } + + scratch_gpa_end = scratch_gpa_beg + len; + if (scratch_gpa_end < scratch_gpa_beg) { + pr_err("vmgexit: scratch length (%#llx) not valid for scratch address (%#llx)\n", + len, scratch_gpa_beg); + return false; + } + + if ((scratch_gpa_beg & PAGE_MASK) == control->ghcb_gpa) { + /* Scratch area begins within GHCB */ + ghcb_scratch_beg = control->ghcb_gpa + + offsetof(struct ghcb, shared_buffer); + ghcb_scratch_end = control->ghcb_gpa + + offsetof(struct ghcb, reserved_1); + + /* + * If the scratch area begins within the GHCB, it must be + * completely contained in the GHCB shared buffer area. + */ + if (scratch_gpa_beg < ghcb_scratch_beg || + scratch_gpa_end > ghcb_scratch_end) { + pr_err("vmgexit: scratch area is outside of GHCB shared buffer area (%#llx - %#llx)\n", + scratch_gpa_beg, scratch_gpa_end); + return false; + } + + scratch_va = (void *)svm->ghcb; + scratch_va += (scratch_gpa_beg - control->ghcb_gpa); + } else { + /* + * The guest memory must be read into a kernel buffer, so + * limit the size + */ + if (len > GHCB_SCRATCH_AREA_LIMIT) { + pr_err("vmgexit: scratch area exceeds KVM limits (%#llx requested, %#llx limit)\n", + len, GHCB_SCRATCH_AREA_LIMIT); + return false; + } + scratch_va = kzalloc(len, GFP_KERNEL); + if (!scratch_va) + return false; + + if (kvm_read_guest(svm->vcpu.kvm, scratch_gpa_beg, scratch_va, len)) { + /* Unable to copy scratch area from guest */ + pr_err("vmgexit: kvm_read_guest for scratch area failed\n"); + + kfree(scratch_va); + return false; + } + + /* + * The scratch area is outside the GHCB. The operation will + * dictate whether the buffer needs to be synced before running + * the vCPU next time (i.e. a read was requested so the data + * must be written back to the guest memory). + */ + svm->ghcb_sa_sync = sync; + svm->ghcb_sa_free = true; + } + + svm->ghcb_sa = scratch_va; + svm->ghcb_sa_len = len; + + return true; +} + static void set_ghcb_msr_bits(struct vcpu_svm *svm, u64 value, u64 mask, unsigned int pos) { @@ -1641,6 +1747,24 @@ int sev_handle_vmgexit(struct vcpu_svm *svm) ret = -EINVAL; switch (exit_code) { + case SVM_VMGEXIT_MMIO_READ: + if (!setup_vmgexit_scratch(svm, true, control->exit_info_2)) + break; + + ret = kvm_sev_es_mmio_read(&svm->vcpu, + control->exit_info_1, + control->exit_info_2, + svm->ghcb_sa); + break; + case SVM_VMGEXIT_MMIO_WRITE: + if (!setup_vmgexit_scratch(svm, false, control->exit_info_2)) + break; + + ret = kvm_sev_es_mmio_write(&svm->vcpu, + control->exit_info_1, + control->exit_info_2, + svm->ghcb_sa); + break; case SVM_VMGEXIT_UNSUPPORTED_EVENT: vcpu_unimpl(&svm->vcpu, "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n", |