To help when debugging failures in the field, if instruction emulation
fails, report the VM exit reason, etc. to userspace in order that it
can be recorded.
The SGX changes here are compiled but untested.
v6:
- More Reviewed-by (Sean).
- Fix "From" (d'oh!).
v5:
- Add some Reviewed-by (Sean).
- Build-time complaint about sizing rather than run-time calculation (Sean).
- Clarify that the format of the auxiliary debug data is undefined (Sean).
- ndata_start -> info_start (Sean).
- sizeof(variable) rather than sizeof(type) (Sean).
v4:
- Update the API for preparing emulation failure report (Sean)
- sgx uses the provided API in all relevant cases (Sean)
- Clarify the intended layout of kvm_run.emulation_failure.
v3:
- Convey any debug data un-flagged after the ABI specified data in
struct emulation_failure (Sean)
- Obey the ABI protocol in sgx_handle_emulation_failure() (Sean)
v2:
- Improve patch comments (dmatlock)
- Intel should provide the full exit reason (dmatlock)
- Pass a boolean rather than flags (dmatlock)
- Use the helper in kvm_task_switch() and kvm_handle_memory_failure()
(dmatlock)
- Describe the exit_reason field of the emulation_failure structure
(dmatlock)
David Edmondson (4):
KVM: x86: Clarify the kvm_run.emulation_failure structure layout
KVM: x86: Get exit_reason as part of kvm_x86_ops.get_exit_info
KVM: x86: On emulation failure, convey the exit reason, etc. to
userspace
KVM: x86: SGX must obey the KVM_INTERNAL_ERROR_EMULATION protocol
arch/x86/include/asm/kvm_host.h | 10 +++--
arch/x86/kvm/svm/svm.c | 8 ++--
arch/x86/kvm/trace.h | 9 ++--
arch/x86/kvm/vmx/nested.c | 2 +-
arch/x86/kvm/vmx/sgx.c | 16 +++-----
arch/x86/kvm/vmx/vmx.c | 11 +++--
arch/x86/kvm/x86.c | 73 ++++++++++++++++++++++++++-------
include/uapi/linux/kvm.h | 14 ++++++-
8 files changed, 99 insertions(+), 44 deletions(-)
--
2.33.0
When passing the failing address and size out to user space, SGX must
ensure not to trample on the earlier fields of the emulation_failure
sub-union of struct kvm_run.
Signed-off-by: David Edmondson <[email protected]>
Reviewed-by: Sean Christopherson <[email protected]>
---
arch/x86/kvm/vmx/sgx.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index 6693ebdc0770..35e7ec91ae86 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -53,11 +53,9 @@ static int sgx_get_encls_gva(struct kvm_vcpu *vcpu, unsigned long offset,
static void sgx_handle_emulation_failure(struct kvm_vcpu *vcpu, u64 addr,
unsigned int size)
{
- vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
- vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
- vcpu->run->internal.ndata = 2;
- vcpu->run->internal.data[0] = addr;
- vcpu->run->internal.data[1] = size;
+ uint64_t data[2] = { addr, size };
+
+ __kvm_prepare_emulation_failure_exit(vcpu, data, ARRAY_SIZE(data));
}
static int sgx_read_hva(struct kvm_vcpu *vcpu, unsigned long hva, void *data,
@@ -112,9 +110,7 @@ static int sgx_inject_fault(struct kvm_vcpu *vcpu, gva_t gva, int trapnr)
* but the error code isn't (yet) plumbed through the ENCLS helpers.
*/
if (trapnr == PF_VECTOR && !boot_cpu_has(X86_FEATURE_SGX2)) {
- vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
- vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
- vcpu->run->internal.ndata = 0;
+ kvm_prepare_emulation_failure_exit(vcpu);
return 0;
}
@@ -155,9 +151,7 @@ static int __handle_encls_ecreate(struct kvm_vcpu *vcpu,
sgx_12_0 = kvm_find_cpuid_entry(vcpu, 0x12, 0);
sgx_12_1 = kvm_find_cpuid_entry(vcpu, 0x12, 1);
if (!sgx_12_0 || !sgx_12_1) {
- vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
- vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
- vcpu->run->internal.ndata = 0;
+ kvm_prepare_emulation_failure_exit(vcpu);
return 0;
}
--
2.33.0