@@ -73,4 +73,15 @@
#define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK)
+/*
+ * Error codes related to GHCB input that can be communicated back to the guest
+ * by setting the lower 32-bits of the GHCB SW_EXITINFO1 field to 2.
+ */
+#define GHCB_ERR_NOT_REGISTERED 1
+#define GHCB_ERR_INVALID_USAGE 2
+#define GHCB_ERR_INVALID_SCRATCH_AREA 3
+#define GHCB_ERR_MISSING_INPUT 4
+#define GHCB_ERR_INVALID_INPUT 5
+#define GHCB_ERR_INVALID_EVENT 6
+
#endif
@@ -2151,24 +2151,29 @@ static void sev_es_sync_from_ghcb(struct vcpu_svm *svm)
memset(ghcb->save.valid_bitmap, 0, sizeof(ghcb->save.valid_bitmap));
}
-static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
+static bool sev_es_validate_vmgexit(struct vcpu_svm *svm)
{
struct kvm_vcpu *vcpu;
struct ghcb *ghcb;
- u64 exit_code = 0;
+ u64 exit_code;
+ u64 reason;
ghcb = svm->sev_es.ghcb;
- /* Only GHCB Usage code 0 is supported */
- if (ghcb->ghcb_usage)
- goto vmgexit_err;
-
/*
- * Retrieve the exit code now even though is may not be marked valid
+ * Retrieve the exit code now even though it may not be marked valid
* as it could help with debugging.
*/
exit_code = ghcb_get_sw_exit_code(ghcb);
+ /* Only GHCB Usage code 0 is supported */
+ if (ghcb->ghcb_usage) {
+ reason = GHCB_ERR_INVALID_USAGE;
+ goto vmgexit_err;
+ }
+
+ reason = GHCB_ERR_MISSING_INPUT;
+
if (!ghcb_sw_exit_code_is_valid(ghcb) ||
!ghcb_sw_exit_info_1_is_valid(ghcb) ||
!ghcb_sw_exit_info_2_is_valid(ghcb))
@@ -2247,30 +2252,34 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
case SVM_VMGEXIT_UNSUPPORTED_EVENT:
break;
default:
+ reason = GHCB_ERR_INVALID_EVENT;
goto vmgexit_err;
}
- return 0;
+ return true;
vmgexit_err:
vcpu = &svm->vcpu;
- if (ghcb->ghcb_usage) {
+ if (reason == GHCB_ERR_INVALID_USAGE) {
vcpu_unimpl(vcpu, "vmgexit: ghcb usage %#x is not valid\n",
ghcb->ghcb_usage);
+ } else if (reason == GHCB_ERR_INVALID_EVENT) {
+ vcpu_unimpl(vcpu, "vmgexit: exit code %#llx is not valid\n",
+ exit_code);
} else {
- vcpu_unimpl(vcpu, "vmgexit: exit reason %#llx is not valid\n",
+ vcpu_unimpl(vcpu, "vmgexit: exit code %#llx input is not valid\n",
exit_code);
dump_ghcb(svm);
}
- vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
- vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON;
- vcpu->run->internal.ndata = 2;
- vcpu->run->internal.data[0] = exit_code;
- vcpu->run->internal.data[1] = vcpu->arch.last_vmentry_cpu;
+ /* Clear the valid entries fields */
+ memset(ghcb->save.valid_bitmap, 0, sizeof(ghcb->save.valid_bitmap));
+
+ ghcb_set_sw_exit_info_1(ghcb, 2);
+ ghcb_set_sw_exit_info_2(ghcb, reason);
- return -EINVAL;
+ return false;
}
void sev_es_unmap_ghcb(struct vcpu_svm *svm)
@@ -2329,7 +2338,7 @@ void pre_sev_run(struct vcpu_svm *svm, int cpu)
}
#define GHCB_SCRATCH_AREA_LIMIT (16ULL * PAGE_SIZE)
-static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len)
+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->sev_es.ghcb;
@@ -2340,14 +2349,14 @@ static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len)
scratch_gpa_beg = ghcb_get_sw_scratch(ghcb);
if (!scratch_gpa_beg) {
pr_err("vmgexit: scratch gpa not provided\n");
- return -EINVAL;
+ goto e_scratch;
}
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 -EINVAL;
+ goto e_scratch;
}
if ((scratch_gpa_beg & PAGE_MASK) == control->ghcb_gpa) {
@@ -2365,7 +2374,7 @@ static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len)
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 -EINVAL;
+ goto e_scratch;
}
scratch_va = (void *)svm->sev_es.ghcb;
@@ -2378,18 +2387,18 @@ static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len)
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 -EINVAL;
+ goto e_scratch;
}
scratch_va = kvzalloc(len, GFP_KERNEL_ACCOUNT);
if (!scratch_va)
- return -ENOMEM;
+ goto e_scratch;
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");
kvfree(scratch_va);
- return -EFAULT;
+ goto e_scratch;
}
/*
@@ -2405,7 +2414,13 @@ static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len)
svm->sev_es.ghcb_sa = scratch_va;
svm->sev_es.ghcb_sa_len = len;
- return 0;
+ return true;
+
+e_scratch:
+ ghcb_set_sw_exit_info_1(ghcb, 2);
+ ghcb_set_sw_exit_info_2(ghcb, GHCB_ERR_INVALID_SCRATCH_AREA);
+
+ return false;
}
static void set_ghcb_msr_bits(struct vcpu_svm *svm, u64 value, u64 mask,
@@ -2456,7 +2471,7 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
ret = svm_invoke_exit_handler(vcpu, SVM_EXIT_CPUID);
if (!ret) {
- ret = -EINVAL;
+ /* Error, keep GHCB MSR value as-is */
break;
}
@@ -2492,10 +2507,13 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
GHCB_MSR_TERM_REASON_POS);
pr_info("SEV-ES guest requested termination: %#llx:%#llx\n",
reason_set, reason_code);
- fallthrough;
+
+ ret = -EINVAL;
+ break;
}
default:
- ret = -EINVAL;
+ /* Error, keep GHCB MSR value as-is */
+ break;
}
trace_kvm_vmgexit_msr_protocol_exit(svm->vcpu.vcpu_id,
@@ -2519,14 +2537,18 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
if (!ghcb_gpa) {
vcpu_unimpl(vcpu, "vmgexit: GHCB gpa is not set\n");
- return -EINVAL;
+
+ /* Without a GHCB, just return right back to the guest */
+ return 1;
}
if (kvm_vcpu_map(vcpu, ghcb_gpa >> PAGE_SHIFT, &svm->sev_es.ghcb_map)) {
/* Unable to map GHCB from guest */
vcpu_unimpl(vcpu, "vmgexit: error mapping GHCB [%#llx] from guest\n",
ghcb_gpa);
- return -EINVAL;
+
+ /* Without a GHCB, just return right back to the guest */
+ return 1;
}
svm->sev_es.ghcb = svm->sev_es.ghcb_map.hva;
@@ -2536,18 +2558,17 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
exit_code = ghcb_get_sw_exit_code(ghcb);
- ret = sev_es_validate_vmgexit(svm);
- if (ret)
- return ret;
+ if (!sev_es_validate_vmgexit(svm))
+ return 1;
sev_es_sync_from_ghcb(svm);
ghcb_set_sw_exit_info_1(ghcb, 0);
ghcb_set_sw_exit_info_2(ghcb, 0);
+ ret = 1;
switch (exit_code) {
case SVM_VMGEXIT_MMIO_READ:
- ret = setup_vmgexit_scratch(svm, true, control->exit_info_2);
- if (ret)
+ if (!setup_vmgexit_scratch(svm, true, control->exit_info_2))
break;
ret = kvm_sev_es_mmio_read(vcpu,
@@ -2556,8 +2577,7 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
svm->sev_es.ghcb_sa);
break;
case SVM_VMGEXIT_MMIO_WRITE:
- ret = setup_vmgexit_scratch(svm, false, control->exit_info_2);
- if (ret)
+ if (!setup_vmgexit_scratch(svm, false, control->exit_info_2))
break;
ret = kvm_sev_es_mmio_write(vcpu,
@@ -2586,14 +2606,10 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
default:
pr_err("svm: vmgexit: unsupported AP jump table request - exit_info_1=%#llx\n",
control->exit_info_1);
- ghcb_set_sw_exit_info_1(ghcb, 1);
- ghcb_set_sw_exit_info_2(ghcb,
- X86_TRAP_UD |
- SVM_EVTINJ_TYPE_EXEPT |
- SVM_EVTINJ_VALID);
+ ghcb_set_sw_exit_info_1(ghcb, 2);
+ ghcb_set_sw_exit_info_2(ghcb, GHCB_ERR_INVALID_INPUT);
}
- ret = 1;
break;
}
case SVM_VMGEXIT_UNSUPPORTED_EVENT:
@@ -2613,7 +2629,6 @@ int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in)
{
int count;
int bytes;
- int r;
if (svm->vmcb->control.exit_info_2 > INT_MAX)
return -EINVAL;
@@ -2622,9 +2637,8 @@ int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in)
if (unlikely(check_mul_overflow(count, size, &bytes)))
return -EINVAL;
- r = setup_vmgexit_scratch(svm, in, bytes);
- if (r)
- return r;
+ if (!setup_vmgexit_scratch(svm, in, bytes))
+ return 1;
return kvm_sev_es_string_io(&svm->vcpu, size, port, svm->sev_es.ghcb_sa,
count, in);