[PATCH v2 0/6] Add SEV-SNP restricted injection hypervisor support

[PATCH v2 0/6] Add SEV-SNP restricted injection hypervisor support

[Melody Wang]

Hi all,

This is a v2 of the restricted injection hypervisor support patches.
 
The previous version was submitted here:
https://lore.kernel.org/r/cover.1722989996.git.huibo.wang@amd.com.

Since the previous submission, one issue reported by the kernel test robot was
fixed.

All comments and review feedback are appreciated.

Thanks. 

Changelog:
v1

Operating systems may not handle unexpected interrupt or exception sequences.
A malicious hypervisor can inject random interrupt or exception sequences,
putting guest drivers or guest OS kernels into an unexpected state, which could
lead to security issues.

To address this concern, SEV-SNP restricts the injection of interrupts and
exceptions to those only allowed by the guest. Restricted Injection disables
all hypervisor-based interrupt queuing and event injection for all vectors,
allowing only a single vector, #HV (28), which is reserved for SNP guest use
but is never generated by hardware. #HV is only permitted to be injected into
VMSAs that execute with Restricted Injection.

Guests operating with Restricted Injection are expected to communicate with the
hypervisor about events via a software-managed para-virtualization interface.
This interface can utilize #HV injection as a doorbell to inform the guest that
new events have occurred. This patch set implements Restricted Injection on the
KVM side directly into VMPL0.

Overview:

The GHCB 2.0 specification[1] defines #HV doorbell page and the #HV doorbell
page NAE event allows for an SEV-SNP guest to register a doorbell page for use
with the hypervisor injection exception (#HV). When Restricted Injection is
active, only #HV exceptions can be injected into the guest, and the hypervisor
follows the GHCB #HV doorbell communication to inject the exception or
interrupt. Restricted Injection can be enabled by setting the bit in
vmsa_features.

The patchset is rebased on the kvm/next (commit 15e1c3d65975524c5c792fcd59f7d89f00402261).

Testing:

The patchset has been tested with the sev-snp guest, ovmf and qemu supporting
restricted injection.

Four test sets:
1.ls -lr /
2.apt update
3.fio
4.perf

Thanks
Melody

Melody Wang (6):
  x86/sev: Define the #HV doorbell page structure
  KVM: SVM: Add support for the SEV-SNP #HV doorbell page NAE event
  KVM: SVM: Inject #HV when restricted injection is active
  KVM: SVM: Inject NMIs when restricted injection is active
  KVM: SVM: Inject MCEs when restricted injection is active
  KVM: SVM: Enable restricted injection for an SEV-SNP guest

 arch/x86/include/asm/cpufeatures.h |   1 +
 arch/x86/include/asm/kvm-x86-ops.h |   1 +
 arch/x86/include/asm/kvm_host.h    |   1 +
 arch/x86/include/asm/sev-common.h  |   1 +
 arch/x86/include/asm/svm.h         |  41 +++++
 arch/x86/include/uapi/asm/kvm.h    |   1 +
 arch/x86/include/uapi/asm/svm.h    |   5 +
 arch/x86/kvm/svm/sev.c             | 277 ++++++++++++++++++++++++++++-
 arch/x86/kvm/svm/svm.c             |  44 ++++-
 arch/x86/kvm/svm/svm.h             |  26 ++-
 arch/x86/kvm/vmx/main.c            |   1 +
 arch/x86/kvm/vmx/vmx.c             |   5 +
 arch/x86/kvm/vmx/x86_ops.h         |   1 +
 arch/x86/kvm/x86.c                 |   8 +
 14 files changed, 408 insertions(+), 5 deletions(-)

-- 
2.34.1

[1] https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/56421.pdf

[PATCH v2 1/6] x86/sev: Define the #HV doorbell page structure

[Melody Wang]

Restricted injection is a feature which enforces additional interrupt and event
injection security protections for a SEV-SNP guest. It disables all
hypervisor-based interrupt queuing and event injection of all vectors except
a new exception vector, #HV (28), which is reserved for SNP guest use, but
never generated by hardware. #HV is only allowed to be injected into VMSAs that
execute with Restricted Injection.

The guests running with the SNP restricted injection feature active limit the
host to ringing a doorbell with a #HV exception.

Define two fields in the #HV doorbell page: a pending event field, and an
EOI assist.

Create the structure definition for the #HV doorbell page as per GHCB
specification.

Co-developed-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
---
 arch/x86/include/asm/svm.h | 41 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index f0dea3750ca9..2b1f4c8daf19 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -516,6 +516,47 @@ struct ghcb {
 	u32 ghcb_usage;
 } __packed;
 
+/*
+ * Hypervisor doorbell page:
+ *
+ * Used when restricted injection is enabled for a VM. One page in size that
+ * is shared between the guest and hypervisor to communicate exception and
+ * interrupt events.
+ */
+struct hvdb_events {
+	/* First 64 bytes of HV doorbell page defined in GHCB specification */
+	union {
+		struct {
+			/* Interrupt vector being injected */
+			u8 vector;
+
+			/* Non-maskable event field (NMI, etc.) */
+			u8 nm_events;
+		};
+
+		struct {
+			/* Non-maskable event indicators */
+			u16 reserved1:		8,
+			    nmi:		1,
+			    mce:		1,
+			    reserved2:		5,
+			    no_further_signal:	1;
+		};
+
+		u16 pending_events;
+	};
+
+	u8 no_eoi_required;
+
+	u8 reserved3[61];
+};
+
+struct hvdb {
+	struct hvdb_events events;
+
+	/* Remainder of the page is for software use */
+	u8 reserved[PAGE_SIZE - sizeof(struct hvdb_events)];
+};
 
 #define EXPECTED_VMCB_SAVE_AREA_SIZE		744
 #define EXPECTED_GHCB_SAVE_AREA_SIZE		1032
-- 
2.34.1

[PATCH v2 2/6] KVM: SVM: Add support for the SEV-SNP #HV doorbell page NAE event

[Melody Wang]

To support the SEV-SNP Restricted Injection feature, the SEV-SNP guest must
register a #HV doorbell page for use with the #HV.

The #HV doorbell page NAE event allows the guest to register a #HV doorbell
page. The NAE event consists of four actions: GET_PREFERRED, SET, QUERY, CLEAR.
Implement the NAE event as per GHCB specification.

Co-developed-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
---
 arch/x86/include/uapi/asm/svm.h |  5 +++
 arch/x86/kvm/svm/sev.c          | 73 +++++++++++++++++++++++++++++++++
 arch/x86/kvm/svm/svm.h          |  2 +
 3 files changed, 80 insertions(+)

diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h
index 1814b413fd57..7905c9be44d1 100644
--- a/arch/x86/include/uapi/asm/svm.h
+++ b/arch/x86/include/uapi/asm/svm.h
@@ -115,6 +115,11 @@
 #define SVM_VMGEXIT_AP_CREATE_ON_INIT		0
 #define SVM_VMGEXIT_AP_CREATE			1
 #define SVM_VMGEXIT_AP_DESTROY			2
+#define SVM_VMGEXIT_HVDB_PAGE                   0x80000014
+#define SVM_VMGEXIT_HVDB_GET_PREFERRED          0
+#define SVM_VMGEXIT_HVDB_SET                    1
+#define SVM_VMGEXIT_HVDB_QUERY                  2
+#define SVM_VMGEXIT_HVDB_CLEAR                  3
 #define SVM_VMGEXIT_SNP_RUN_VMPL		0x80000018
 #define SVM_VMGEXIT_HV_FEATURES			0x8000fffd
 #define SVM_VMGEXIT_TERM_REQUEST		0x8000fffe
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 714c517dd4b7..e65867ea768d 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3410,6 +3410,10 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 		    control->exit_info_1 == control->exit_info_2)
 			goto vmgexit_err;
 		break;
+	case SVM_VMGEXIT_HVDB_PAGE:
+		if (!sev_snp_guest(vcpu->kvm))
+			goto vmgexit_err;
+		break;
 	default:
 		reason = GHCB_ERR_INVALID_EVENT;
 		goto vmgexit_err;
@@ -4125,6 +4129,66 @@ static int snp_handle_ext_guest_req(struct vcpu_svm *svm, gpa_t req_gpa, gpa_t r
 	return 1; /* resume guest */
 }
 
+static int sev_snp_hv_doorbell_page(struct vcpu_svm *svm)
+{
+	struct kvm_vcpu *vcpu = &svm->vcpu;
+	struct kvm_host_map hvdb_map;
+	gpa_t hvdb_gpa;
+	u64 request;
+
+	if (!sev_snp_guest(vcpu->kvm))
+		return -EINVAL;
+
+	request = svm->vmcb->control.exit_info_1;
+	hvdb_gpa = svm->vmcb->control.exit_info_2;
+
+	switch (request) {
+	case SVM_VMGEXIT_HVDB_GET_PREFERRED:
+		ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, ~0ULL);
+		break;
+	case SVM_VMGEXIT_HVDB_SET:
+		svm->sev_es.hvdb_gpa = INVALID_PAGE;
+
+		if (!PAGE_ALIGNED(hvdb_gpa)) {
+			vcpu_unimpl(vcpu, "vmgexit: unaligned #HV doorbell page address [%#llx] from guest\n",
+				    hvdb_gpa);
+			return -EINVAL;
+		}
+
+		if (!page_address_valid(vcpu, hvdb_gpa)) {
+			vcpu_unimpl(vcpu, "vmgexit: invalid #HV doorbell page address [%#llx] from guest\n",
+				    hvdb_gpa);
+			return -EINVAL;
+		}
+
+		/* Map and unmap the GPA just to be sure the GPA is valid */
+		if (kvm_vcpu_map(vcpu, gpa_to_gfn(hvdb_gpa), &hvdb_map)) {
+			/* Unable to map #HV doorbell page from guest */
+			vcpu_unimpl(vcpu, "vmgexit: error mapping #HV doorbell page [%#llx] from guest\n",
+				    hvdb_gpa);
+			return -EINVAL;
+		}
+		kvm_vcpu_unmap(vcpu, &hvdb_map, true);
+
+		svm->sev_es.hvdb_gpa = hvdb_gpa;
+		fallthrough;
+	case SVM_VMGEXIT_HVDB_QUERY:
+		ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, svm->sev_es.hvdb_gpa);
+		break;
+	case SVM_VMGEXIT_HVDB_CLEAR:
+		svm->sev_es.hvdb_gpa = INVALID_PAGE;
+		break;
+	default:
+		svm->sev_es.hvdb_gpa = INVALID_PAGE;
+
+		vcpu_unimpl(vcpu, "vmgexit: invalid #HV doorbell page request [%#llx] from guest\n",
+			    request);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 {
 	struct vmcb_control_area *control = &svm->vmcb->control;
@@ -4405,6 +4469,14 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 	case SVM_VMGEXIT_EXT_GUEST_REQUEST:
 		ret = snp_handle_ext_guest_req(svm, control->exit_info_1, control->exit_info_2);
 		break;
+	case SVM_VMGEXIT_HVDB_PAGE:
+		if (sev_snp_hv_doorbell_page(svm)) {
+			ghcb_set_sw_exit_info_1(svm->sev_es.ghcb, 2);
+			ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, GHCB_ERR_INVALID_INPUT);
+		}
+
+		ret = 1;
+		break;
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
 		vcpu_unimpl(vcpu,
 			    "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n",
@@ -4572,6 +4644,7 @@ void sev_es_vcpu_reset(struct vcpu_svm *svm)
 					    sev_enc_bit));
 
 	mutex_init(&svm->sev_es.snp_vmsa_mutex);
+	svm->sev_es.hvdb_gpa = INVALID_PAGE;
 }
 
 void sev_es_prepare_switch_to_guest(struct vcpu_svm *svm, struct sev_es_save_area *hostsa)
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 76107c7d0595..f0f14801e122 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -225,6 +225,8 @@ struct vcpu_sev_es_state {
 	gpa_t snp_vmsa_gpa;
 	bool snp_ap_waiting_for_reset;
 	bool snp_has_guest_vmsa;
+
+	gpa_t hvdb_gpa;
 };
 
 struct vcpu_svm {
-- 
2.34.1

[PATCH v2 3/6] KVM: SVM: Inject #HV when restricted injection is active

[Melody Wang]

When restricted injection is active, only #HV exceptions can be injected into
the SEV-SNP guest.

Detect that restricted injection feature is active for the guest, and then
follow the #HV doorbell communication from the GHCB specification to inject the
interrupt or exception.

Co-developed-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
---
 arch/x86/include/uapi/asm/kvm.h |   1 +
 arch/x86/kvm/svm/sev.c          | 153 ++++++++++++++++++++++++++++++++
 arch/x86/kvm/svm/svm.c          |  19 +++-
 arch/x86/kvm/svm/svm.h          |  21 ++++-
 4 files changed, 190 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index bf57a824f722..f5d85174e658 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -35,6 +35,7 @@
 #define MC_VECTOR 18
 #define XM_VECTOR 19
 #define VE_VECTOR 20
+#define HV_VECTOR 28
 
 /* Select x86 specific features in <linux/kvm.h> */
 #define __KVM_HAVE_PIT
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index e65867ea768d..f7623fa64307 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -5023,3 +5023,156 @@ int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn)
 
 	return level;
 }
+
+static void prepare_hv_injection(struct vcpu_svm *svm, struct hvdb *hvdb)
+{
+	if (hvdb->events.no_further_signal)
+		return;
+
+	svm->vmcb->control.event_inj = HV_VECTOR |
+				       SVM_EVTINJ_TYPE_EXEPT |
+				       SVM_EVTINJ_VALID;
+	svm->vmcb->control.event_inj_err = 0;
+
+	hvdb->events.no_further_signal = 1;
+}
+
+static void unmap_hvdb(struct kvm_vcpu *vcpu, struct kvm_host_map *map)
+{
+	kvm_vcpu_unmap(vcpu, map, true);
+}
+
+static struct hvdb *map_hvdb(struct kvm_vcpu *vcpu, struct kvm_host_map *map)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if (!VALID_PAGE(svm->sev_es.hvdb_gpa))
+		return NULL;
+
+	if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->sev_es.hvdb_gpa), map)) {
+		/* Unable to map #HV doorbell page from guest */
+		vcpu_unimpl(vcpu, "snp: error mapping #HV doorbell page [%#llx] from guest\n",
+			    svm->sev_es.hvdb_gpa);
+
+		return NULL;
+	}
+
+	return map->hva;
+}
+
+static bool __sev_snp_inject(enum inject_type type, struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	struct kvm_host_map hvdb_map;
+	struct hvdb *hvdb;
+
+	hvdb = map_hvdb(vcpu, &hvdb_map);
+	if (!hvdb)
+		return false;
+
+	hvdb->events.vector = vcpu->arch.interrupt.nr;
+
+	prepare_hv_injection(svm, hvdb);
+
+	unmap_hvdb(vcpu, &hvdb_map);
+
+	return true;
+}
+
+bool sev_snp_queue_exception(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if (!sev_snp_is_rinj_active(vcpu))
+		return false;
+
+	/*
+	 * Restricted injection is enabled, only #HV is supported.
+	 * If the vector is not HV_VECTOR, do not inject the exception,
+	 * then return true to skip the original injection path.
+	 */
+	if (WARN_ONCE(vcpu->arch.exception.vector != HV_VECTOR,
+		      "restricted injection enabled, exception %u injection not supported\n",
+		      vcpu->arch.exception.vector))
+		return true;
+
+	/*
+	 * An intercept likely occurred during #HV delivery, so re-inject it
+	 * using the current HVDB pending event values.
+	 */
+	svm->vmcb->control.event_inj = HV_VECTOR |
+				       SVM_EVTINJ_TYPE_EXEPT |
+				       SVM_EVTINJ_VALID;
+	svm->vmcb->control.event_inj_err = 0;
+
+	return true;
+}
+
+bool sev_snp_inject(enum inject_type type, struct kvm_vcpu *vcpu)
+{
+	if (!sev_snp_is_rinj_active(vcpu))
+		return false;
+
+	return __sev_snp_inject(type, vcpu);
+}
+
+void sev_snp_cancel_injection(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	struct kvm_host_map hvdb_map;
+	struct hvdb *hvdb;
+
+	if (!sev_snp_is_rinj_active(vcpu))
+		return;
+
+	if (!svm->vmcb->control.event_inj)
+		return;
+
+	if ((svm->vmcb->control.event_inj & SVM_EVTINJ_VEC_MASK) != HV_VECTOR)
+		return;
+
+	/*
+	 * Copy the information in the doorbell page into the event injection
+	 * fields to complete the cancellation flow.
+	 */
+	hvdb = map_hvdb(vcpu, &hvdb_map);
+	if (!hvdb)
+		return;
+
+	if (!hvdb->events.pending_events) {
+		/* No pending events, then event_inj field should be 0 */
+		WARN_ON_ONCE(svm->vmcb->control.event_inj);
+		goto out;
+	}
+
+	/* Copy info back into event_inj field (replaces #HV) */
+	svm->vmcb->control.event_inj = SVM_EVTINJ_VALID;
+
+	if (hvdb->events.vector)
+		svm->vmcb->control.event_inj |= hvdb->events.vector |
+						SVM_EVTINJ_TYPE_INTR;
+
+	hvdb->events.pending_events = 0;
+
+out:
+	unmap_hvdb(vcpu, &hvdb_map);
+}
+
+bool sev_snp_blocked(enum inject_type type, struct kvm_vcpu *vcpu)
+{
+	struct kvm_host_map hvdb_map;
+	struct hvdb *hvdb;
+	bool blocked;
+
+	/* Indicate interrupts are blocked if doorbell page can't be mapped */
+	hvdb = map_hvdb(vcpu, &hvdb_map);
+	if (!hvdb)
+		return true;
+
+	/* Indicate interrupts blocked based on guest acknowledgment */
+	blocked = !!hvdb->events.vector;
+
+	unmap_hvdb(vcpu, &hvdb_map);
+
+	return blocked;
+}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d6f252555ab3..a48388d99c97 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -447,6 +447,9 @@ static int svm_update_soft_interrupt_rip(struct kvm_vcpu *vcpu)
 	svm->soft_int_old_rip = old_rip;
 	svm->soft_int_next_rip = rip;
 
+	if (sev_snp_queue_exception(vcpu))
+		return 0;
+
 	if (nrips)
 		kvm_rip_write(vcpu, old_rip);
 
@@ -467,6 +470,9 @@ static void svm_inject_exception(struct kvm_vcpu *vcpu)
 	    svm_update_soft_interrupt_rip(vcpu))
 		return;
 
+	if (sev_snp_queue_exception(vcpu))
+		return;
+
 	svm->vmcb->control.event_inj = ex->vector
 		| SVM_EVTINJ_VALID
 		| (ex->has_error_code ? SVM_EVTINJ_VALID_ERR : 0)
@@ -3662,10 +3668,12 @@ static void svm_inject_irq(struct kvm_vcpu *vcpu, bool reinjected)
 
 	trace_kvm_inj_virq(vcpu->arch.interrupt.nr,
 			   vcpu->arch.interrupt.soft, reinjected);
-	++vcpu->stat.irq_injections;
 
-	svm->vmcb->control.event_inj = vcpu->arch.interrupt.nr |
-				       SVM_EVTINJ_VALID | type;
+	if (!sev_snp_inject(INJECT_IRQ, vcpu))
+		svm->vmcb->control.event_inj = vcpu->arch.interrupt.nr |
+						SVM_EVTINJ_VALID | type;
+
+	++vcpu->stat.irq_injections;
 }
 
 void svm_complete_interrupt_delivery(struct kvm_vcpu *vcpu, int delivery_mode,
@@ -3810,6 +3818,9 @@ bool svm_interrupt_blocked(struct kvm_vcpu *vcpu)
 	if (!gif_set(svm))
 		return true;
 
+	if (sev_snp_is_rinj_active(vcpu))
+		return sev_snp_blocked(INJECT_IRQ, vcpu);
+
 	if (is_guest_mode(vcpu)) {
 		/* As long as interrupts are being delivered...  */
 		if ((svm->nested.ctl.int_ctl & V_INTR_MASKING_MASK)
@@ -4128,6 +4139,8 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu)
 	struct vcpu_svm *svm = to_svm(vcpu);
 	struct vmcb_control_area *control = &svm->vmcb->control;
 
+	sev_snp_cancel_injection(vcpu);
+
 	control->exit_int_info = control->event_inj;
 	control->exit_int_info_err = control->event_inj_err;
 	control->event_inj = 0;
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index f0f14801e122..95c0a7070bd1 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -41,6 +41,10 @@ extern bool x2avic_enabled;
 extern bool vnmi;
 extern int lbrv;
 
+enum inject_type {
+	INJECT_IRQ,
+};
+
 /*
  * Clean bits in VMCB.
  * VMCB_ALL_CLEAN_MASK might also need to
@@ -751,6 +755,17 @@ void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu);
 int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order);
 void sev_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end);
 int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn);
+bool sev_snp_queue_exception(struct kvm_vcpu *vcpu);
+bool sev_snp_inject(enum inject_type type, struct kvm_vcpu *vcpu);
+void sev_snp_cancel_injection(struct kvm_vcpu *vcpu);
+bool sev_snp_blocked(enum inject_type type, struct kvm_vcpu *vcpu);
+static inline bool sev_snp_is_rinj_active(struct kvm_vcpu *vcpu)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(vcpu->kvm)->sev_info;
+
+	return sev_snp_guest(vcpu->kvm) &&
+		(sev->vmsa_features & SVM_SEV_FEAT_RESTRICTED_INJECTION);
+};
 #else
 static inline struct page *snp_safe_alloc_page_node(int node, gfp_t gfp)
 {
@@ -781,7 +796,11 @@ static inline int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn)
 {
 	return 0;
 }
-
+static inline bool sev_snp_queue_exception(struct kvm_vcpu *vcpu) { return false; }
+static inline bool sev_snp_inject(enum inject_type type, struct kvm_vcpu *vcpu) { return false; }
+static inline void sev_snp_cancel_injection(struct kvm_vcpu *vcpu) {}
+static inline bool sev_snp_blocked(enum inject_type type, struct kvm_vcpu *vcpu) { return false; }
+static inline bool sev_snp_is_rinj_active(struct kvm_vcpu *vcpu) { return false; }
 #endif
 
 /* vmenter.S */
-- 
2.34.1

[PATCH v2 4/6] KVM: SVM: Inject NMIs when restricted injection is active

[Melody Wang]

When restricted injection is active, only #HV exceptions can be injected into
the SEV-SNP guest.

Detect that restricted injection feature is active for the guest, and then
follow the #HV doorbell communication from the GHCB specification to inject
NMIs.

Co-developed-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
---
 arch/x86/kvm/svm/sev.c | 19 ++++++++++++++++---
 arch/x86/kvm/svm/svm.c |  8 ++++++++
 arch/x86/kvm/svm/svm.h |  1 +
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index f7623fa64307..9102f7e39c52 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -5070,7 +5070,10 @@ static bool __sev_snp_inject(enum inject_type type, struct kvm_vcpu *vcpu)
 	if (!hvdb)
 		return false;
 
-	hvdb->events.vector = vcpu->arch.interrupt.nr;
+	if (type == INJECT_NMI)
+		hvdb->events.nmi = 1;
+	else
+		hvdb->events.vector = vcpu->arch.interrupt.nr;
 
 	prepare_hv_injection(svm, hvdb);
 
@@ -5148,10 +5151,17 @@ void sev_snp_cancel_injection(struct kvm_vcpu *vcpu)
 	/* Copy info back into event_inj field (replaces #HV) */
 	svm->vmcb->control.event_inj = SVM_EVTINJ_VALID;
 
+	/*
+	 * KVM only injects a single event each time (prepare_hv_injection),
+	 * so when events.nmi is true, the vector will be zero
+	 */
 	if (hvdb->events.vector)
 		svm->vmcb->control.event_inj |= hvdb->events.vector |
 						SVM_EVTINJ_TYPE_INTR;
 
+	if (hvdb->events.nmi)
+		svm->vmcb->control.event_inj |= SVM_EVTINJ_TYPE_NMI;
+
 	hvdb->events.pending_events = 0;
 
 out:
@@ -5169,8 +5179,11 @@ bool sev_snp_blocked(enum inject_type type, struct kvm_vcpu *vcpu)
 	if (!hvdb)
 		return true;
 
-	/* Indicate interrupts blocked based on guest acknowledgment */
-	blocked = !!hvdb->events.vector;
+	/* Indicate NMIs and interrupts blocked based on guest acknowledgment */
+	if (type == INJECT_NMI)
+		blocked = hvdb->events.nmi;
+	else
+		blocked = !!hvdb->events.vector;
 
 	unmap_hvdb(vcpu, &hvdb_map);
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index a48388d99c97..d9c572344f0c 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3602,6 +3602,9 @@ static void svm_inject_nmi(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
+	if (sev_snp_inject(INJECT_NMI, vcpu))
+		goto status;
+
 	svm->vmcb->control.event_inj = SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_NMI;
 
 	if (svm->nmi_l1_to_l2)
@@ -3616,6 +3619,8 @@ static void svm_inject_nmi(struct kvm_vcpu *vcpu)
 		svm->nmi_masked = true;
 		svm_set_iret_intercept(svm);
 	}
+
+status:
 	++vcpu->stat.nmi_injections;
 }
 
@@ -3786,6 +3791,9 @@ bool svm_nmi_blocked(struct kvm_vcpu *vcpu)
 	if (!gif_set(svm))
 		return true;
 
+	if (sev_snp_is_rinj_active(vcpu))
+		return sev_snp_blocked(INJECT_NMI, vcpu);
+
 	if (is_guest_mode(vcpu) && nested_exit_on_nmi(svm))
 		return false;
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 95c0a7070bd1..f60ff6229ff4 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -43,6 +43,7 @@ extern int lbrv;
 
 enum inject_type {
 	INJECT_IRQ,
+	INJECT_NMI,
 };
 
 /*
-- 
2.34.1

[PATCH v2 5/6] KVM: SVM: Inject MCEs when restricted injection is active

[Melody Wang]

When restricted injection is active, only #HV exceptions can be injected into
the SEV-SNP guest.

Detect that restricted injection feature is active for the guest, and then
follow the #HV doorbell communication from the GHCB specification to inject the
MCEs.

Co-developed-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
---
 arch/x86/include/asm/kvm-x86-ops.h |  1 +
 arch/x86/include/asm/kvm_host.h    |  1 +
 arch/x86/kvm/svm/sev.c             | 16 ++++++++++++++--
 arch/x86/kvm/svm/svm.c             | 17 +++++++++++++++++
 arch/x86/kvm/svm/svm.h             |  2 ++
 arch/x86/kvm/vmx/main.c            |  1 +
 arch/x86/kvm/vmx/vmx.c             |  5 +++++
 arch/x86/kvm/vmx/x86_ops.h         |  1 +
 arch/x86/kvm/x86.c                 |  8 ++++++++
 9 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 68ad4f923664..9e5764a8e031 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -76,6 +76,7 @@ KVM_X86_OP(inject_exception)
 KVM_X86_OP(cancel_injection)
 KVM_X86_OP(interrupt_allowed)
 KVM_X86_OP(nmi_allowed)
+KVM_X86_OP_OPTIONAL(mce_allowed)
 KVM_X86_OP(get_nmi_mask)
 KVM_X86_OP(set_nmi_mask)
 KVM_X86_OP(enable_nmi_window)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 94e7b5a4fafe..cb1608a69144 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1715,6 +1715,7 @@ struct kvm_x86_ops {
 	void (*cancel_injection)(struct kvm_vcpu *vcpu);
 	int (*interrupt_allowed)(struct kvm_vcpu *vcpu, bool for_injection);
 	int (*nmi_allowed)(struct kvm_vcpu *vcpu, bool for_injection);
+	int (*mce_allowed)(struct kvm_vcpu *vcpu);
 	bool (*get_nmi_mask)(struct kvm_vcpu *vcpu);
 	void (*set_nmi_mask)(struct kvm_vcpu *vcpu, bool masked);
 	/* Whether or not a virtual NMI is pending in hardware. */
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 9102f7e39c52..0b898b16026b 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -5072,6 +5072,8 @@ static bool __sev_snp_inject(enum inject_type type, struct kvm_vcpu *vcpu)
 
 	if (type == INJECT_NMI)
 		hvdb->events.nmi = 1;
+	else if (type == INJECT_MCE)
+		hvdb->events.mce = 1;
 	else
 		hvdb->events.vector = vcpu->arch.interrupt.nr;
 
@@ -5089,6 +5091,11 @@ bool sev_snp_queue_exception(struct kvm_vcpu *vcpu)
 	if (!sev_snp_is_rinj_active(vcpu))
 		return false;
 
+	if (vcpu->arch.exception.vector == MC_VECTOR) {
+		if (__sev_snp_inject(INJECT_MCE, vcpu))
+			return true;
+	}
+
 	/*
 	 * Restricted injection is enabled, only #HV is supported.
 	 * If the vector is not HV_VECTOR, do not inject the exception,
@@ -5153,7 +5160,7 @@ void sev_snp_cancel_injection(struct kvm_vcpu *vcpu)
 
 	/*
 	 * KVM only injects a single event each time (prepare_hv_injection),
-	 * so when events.nmi is true, the vector will be zero
+	 * so when events.nmi is true, the mce and vector will be zero
 	 */
 	if (hvdb->events.vector)
 		svm->vmcb->control.event_inj |= hvdb->events.vector |
@@ -5162,6 +5169,9 @@ void sev_snp_cancel_injection(struct kvm_vcpu *vcpu)
 	if (hvdb->events.nmi)
 		svm->vmcb->control.event_inj |= SVM_EVTINJ_TYPE_NMI;
 
+	if (hvdb->events.mce)
+		svm->vmcb->control.event_inj |= MC_VECTOR | SVM_EVTINJ_TYPE_EXEPT;
+
 	hvdb->events.pending_events = 0;
 
 out:
@@ -5179,9 +5189,11 @@ bool sev_snp_blocked(enum inject_type type, struct kvm_vcpu *vcpu)
 	if (!hvdb)
 		return true;
 
-	/* Indicate NMIs and interrupts blocked based on guest acknowledgment */
+	/* Indicate NMIs, MCEs and interrupts blocked based on guest acknowledgment */
 	if (type == INJECT_NMI)
 		blocked = hvdb->events.nmi;
+	else if (type == INJECT_MCE)
+		blocked = hvdb->events.mce;
 	else
 		blocked = !!hvdb->events.vector;
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d9c572344f0c..1c13c5da6eea 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3867,6 +3867,22 @@ static int svm_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection)
 	return 1;
 }
 
+bool svm_mce_blocked(struct kvm_vcpu *vcpu)
+{
+	if (sev_snp_is_rinj_active(vcpu))
+		return sev_snp_blocked(INJECT_MCE, vcpu);
+
+	return false;
+}
+
+static int svm_mce_allowed(struct kvm_vcpu *vcpu)
+{
+	if (svm_mce_blocked(vcpu))
+		return 0;
+
+	return 1;
+}
+
 static void svm_enable_irq_window(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -5066,6 +5082,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.cancel_injection = svm_cancel_injection,
 	.interrupt_allowed = svm_interrupt_allowed,
 	.nmi_allowed = svm_nmi_allowed,
+	.mce_allowed = svm_mce_allowed,
 	.get_nmi_mask = svm_get_nmi_mask,
 	.set_nmi_mask = svm_set_nmi_mask,
 	.enable_nmi_window = svm_enable_nmi_window,
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index f60ff6229ff4..0cf32954589f 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -44,6 +44,7 @@ extern int lbrv;
 enum inject_type {
 	INJECT_IRQ,
 	INJECT_NMI,
+	INJECT_MCE,
 };
 
 /*
@@ -602,6 +603,7 @@ void svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4);
 void disable_nmi_singlestep(struct vcpu_svm *svm);
 bool svm_smi_blocked(struct kvm_vcpu *vcpu);
 bool svm_nmi_blocked(struct kvm_vcpu *vcpu);
+bool svm_mce_blocked(struct kvm_vcpu *vcpu);
 bool svm_interrupt_blocked(struct kvm_vcpu *vcpu);
 void svm_set_gif(struct vcpu_svm *svm, bool value);
 int svm_invoke_exit_handler(struct kvm_vcpu *vcpu, u64 exit_code);
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 0bf35ebe8a1b..c3a49a3b7f21 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -84,6 +84,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.cancel_injection = vmx_cancel_injection,
 	.interrupt_allowed = vmx_interrupt_allowed,
 	.nmi_allowed = vmx_nmi_allowed,
+	.mce_allowed = vmx_mce_allowed,
 	.get_nmi_mask = vmx_get_nmi_mask,
 	.set_nmi_mask = vmx_set_nmi_mask,
 	.enable_nmi_window = vmx_enable_nmi_window,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index f18c2d8c7476..b3dce5d95329 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5093,6 +5093,11 @@ int vmx_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection)
 	return !vmx_interrupt_blocked(vcpu);
 }
 
+int vmx_mce_allowed(struct kvm_vcpu *vcpu)
+{
+	return 1;
+}
+
 int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr)
 {
 	void __user *ret;
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index ce3221cd1d01..b2b1a3bb4eb3 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -92,6 +92,7 @@ void vmx_inject_exception(struct kvm_vcpu *vcpu);
 void vmx_cancel_injection(struct kvm_vcpu *vcpu);
 int vmx_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection);
 int vmx_nmi_allowed(struct kvm_vcpu *vcpu, bool for_injection);
+int vmx_mce_allowed(struct kvm_vcpu *vcpu);
 bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu);
 void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked);
 void vmx_enable_nmi_window(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 70219e406987..2007598af873 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10485,6 +10485,12 @@ static int kvm_check_and_inject_events(struct kvm_vcpu *vcpu,
 			}
 		}
 
+		if (vcpu->arch.exception.vector == MC_VECTOR) {
+			r = static_call(kvm_x86_mce_allowed)(vcpu);
+			if (!r)
+				goto out_except;
+		}
+
 		kvm_inject_exception(vcpu);
 
 		vcpu->arch.exception.pending = false;
@@ -10493,6 +10499,8 @@ static int kvm_check_and_inject_events(struct kvm_vcpu *vcpu,
 		can_inject = false;
 	}
 
+out_except:
+
 	/* Don't inject interrupts if the user asked to avoid doing so */
 	if (vcpu->guest_debug & KVM_GUESTDBG_BLOCKIRQ)
 		return 0;
-- 
2.34.1

[PATCH v2 6/6] KVM: SVM: Enable restricted injection for an SEV-SNP guest

[Melody Wang]

Enable the restricted injection in an SEV-SNP guest by setting the restricted
injection bit in the VMSA SEV features field (SEV_FEATURES[3]) from QEMU.

Add the restricted injection supporting the hypervisor advertised features.

Co-developed-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
---
 arch/x86/include/asm/cpufeatures.h |  1 +
 arch/x86/include/asm/sev-common.h  |  1 +
 arch/x86/kvm/svm/sev.c             | 26 +++++++++++++++++++++++++-
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index dd4682857c12..ff8466405409 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -446,6 +446,7 @@
 #define X86_FEATURE_SEV_SNP		(19*32+ 4) /* "sev_snp" AMD Secure Encrypted Virtualization - Secure Nested Paging */
 #define X86_FEATURE_V_TSC_AUX		(19*32+ 9) /* Virtual TSC_AUX */
 #define X86_FEATURE_SME_COHERENT	(19*32+10) /* AMD hardware-enforced cache coherency */
+#define X86_FEATURE_RESTRICTED_INJECTION	(19*32+12) /* AMD SEV Restricted Injection */
 #define X86_FEATURE_DEBUG_SWAP		(19*32+14) /* "debug_swap" AMD SEV-ES full debug state swap support */
 #define X86_FEATURE_SVSM		(19*32+28) /* "svsm" SVSM present */
 
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 98726c2b04f8..f409893ad1a5 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -136,6 +136,7 @@ enum psc_op {
 
 #define GHCB_HV_FT_SNP			BIT_ULL(0)
 #define GHCB_HV_FT_SNP_AP_CREATION	BIT_ULL(1)
+#define GHCB_HV_FT_SNP_RINJ		(BIT_ULL(2) | GHCB_HV_FT_SNP_AP_CREATION)
 #define GHCB_HV_FT_SNP_MULTI_VMPL	BIT_ULL(5)
 
 /*
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 0b898b16026b..bad50378c898 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -39,7 +39,9 @@
 #define GHCB_VERSION_DEFAULT	2ULL
 #define GHCB_VERSION_MIN	1ULL
 
-#define GHCB_HV_FT_SUPPORTED	(GHCB_HV_FT_SNP | GHCB_HV_FT_SNP_AP_CREATION)
+#define GHCB_HV_FT_SUPPORTED	(GHCB_HV_FT_SNP |		\
+				 GHCB_HV_FT_SNP_AP_CREATION |	\
+				 GHCB_HV_FT_SNP_RINJ)
 
 /* enable/disable SEV support */
 static bool sev_enabled = true;
@@ -56,6 +58,10 @@ module_param_named(sev_snp, sev_snp_enabled, bool, 0444);
 /* enable/disable SEV-ES DebugSwap support */
 static bool sev_es_debug_swap_enabled = true;
 module_param_named(debug_swap, sev_es_debug_swap_enabled, bool, 0444);
+
+/* enable/disable SEV-SNP Restricted Injection support */
+static bool sev_snp_restricted_injection_enabled = true;
+module_param_named(restricted_injection, sev_snp_restricted_injection_enabled, bool, 0444);
 static u64 sev_supported_vmsa_features;
 
 #define AP_RESET_HOLD_NONE		0
@@ -3079,6 +3085,12 @@ void __init sev_hardware_setup(void)
 	sev_supported_vmsa_features = 0;
 	if (sev_es_debug_swap_enabled)
 		sev_supported_vmsa_features |= SVM_SEV_FEAT_DEBUG_SWAP;
+
+	if (!sev_snp_enabled || !cpu_feature_enabled(X86_FEATURE_RESTRICTED_INJECTION))
+		sev_snp_restricted_injection_enabled = false;
+
+	if (sev_snp_restricted_injection_enabled)
+		sev_supported_vmsa_features |= SVM_SEV_FEAT_RESTRICTED_INJECTION;
 }
 
 void sev_hardware_unsetup(void)
@@ -4556,6 +4568,15 @@ void sev_vcpu_after_set_cpuid(struct vcpu_svm *svm)
 		sev_es_vcpu_after_set_cpuid(svm);
 }
 
+static void sev_snp_init_vmcb(struct vcpu_svm *svm)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(svm->vcpu.kvm)->sev_info;
+
+	/* V_NMI is not supported when Restricted Injection is enabled */
+	if (sev->vmsa_features & SVM_SEV_FEAT_RESTRICTED_INJECTION)
+		svm->vmcb->control.int_ctl &= ~V_NMI_ENABLE_MASK;
+}
+
 static void sev_es_init_vmcb(struct vcpu_svm *svm)
 {
 	struct vmcb *vmcb = svm->vmcb01.ptr;
@@ -4613,6 +4634,9 @@ static void sev_es_init_vmcb(struct vcpu_svm *svm)
 	/* Clear intercepts on selected MSRs */
 	set_msr_interception(vcpu, svm->msrpm, MSR_EFER, 1, 1);
 	set_msr_interception(vcpu, svm->msrpm, MSR_IA32_CR_PAT, 1, 1);
+
+	if (sev_snp_guest(vcpu->kvm))
+		sev_snp_init_vmcb(svm);
 }
 
 void sev_init_vmcb(struct vcpu_svm *svm)
-- 
2.34.1

Re: [PATCH v2 3/6] KVM: SVM: Inject #HV when restricted injection is active

[Lai Jiangshan]

Hello

On Tue, Sep 10, 2024 at 2:05 PM Melody Wang <huibo.wang@amd.com> wrote:

> +static bool __sev_snp_inject(enum inject_type type, struct kvm_vcpu *vcpu)
> +{
> +       struct vcpu_svm *svm = to_svm(vcpu);
> +       struct kvm_host_map hvdb_map;
> +       struct hvdb *hvdb;
> +
> +       hvdb = map_hvdb(vcpu, &hvdb_map);
> +       if (!hvdb)
> +               return false;

          old_vector = hvdb->events.vector;

> +
> +       hvdb->events.vector = vcpu->arch.interrupt.nr;
> +
> +       prepare_hv_injection(svm, hvdb);

The specification recommends saving an HV injection on the following condition:

    if (!(type == INJECT_IRQ && old_vector))
         prepare_hv_injection(svm, hvdb)

If PendingEvent.Vector was previously non-zero, because the guest has
not yet chosen to acknowledge the interrupt, the previous vector
number can be overwritten by the new vector number without sending
another #HV (regardless of the value of PendingEvent.NoFurtherSignal),
because the guest should already have been informed that a vector was
pending.


> +
> +       unmap_hvdb(vcpu, &hvdb_map);
> +
> +       return true;
> +}
> +

Re: [PATCH v2 5/6] KVM: SVM: Inject MCEs when restricted injection is active

[Lai Jiangshan]

Hello

On Tue, Sep 10, 2024 at 2:06 PM Melody Wang <huibo.wang@amd.com> wrote:

> @@ -5153,7 +5160,7 @@ void sev_snp_cancel_injection(struct kvm_vcpu *vcpu)
>
>         /*
>          * KVM only injects a single event each time (prepare_hv_injection),
> -        * so when events.nmi is true, the vector will be zero
> +        * so when events.nmi is true, the mce and vector will be zero
>          */

This comment seems ambiguous, and in the following code,
events.nmi/mce/vector appears to be able to be true simultaneously,
rather than being mutually exclusive.


>         if (hvdb->events.vector)
>                 svm->vmcb->control.event_inj |= hvdb->events.vector |
> @@ -5162,6 +5169,9 @@ void sev_snp_cancel_injection(struct kvm_vcpu *vcpu)
>         if (hvdb->events.nmi)
>                 svm->vmcb->control.event_inj |= SVM_EVTINJ_TYPE_NMI;
>
> +       if (hvdb->events.mce)
> +               svm->vmcb->control.event_inj |= MC_VECTOR | SVM_EVTINJ_TYPE_EXEPT;