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Date: Wed, 29 Sep 2021 17:53:28 +0200
From: Joerg Roedel <joro@...tes.org>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <seanjc@...gle.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>, x86@...nel.org,
Brijesh Singh <brijesh.singh@....com>,
Tom Lendacky <thomas.lendacky@....com>, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org, Joerg Roedel <jroedel@...e.de>
Subject: [PATCH v4 3/5] KVM: SVM: Add support to handle AP reset MSR protocol
From: Tom Lendacky <thomas.lendacky@....com>
Add support for AP Reset Hold being invoked using the GHCB MSR protocol,
available in version 2 of the GHCB specification.
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
arch/x86/include/asm/kvm_host.h | 10 ++++++-
arch/x86/kvm/svm/sev.c | 48 ++++++++++++++++++++++++++-------
arch/x86/kvm/x86.c | 5 +++-
3 files changed, 51 insertions(+), 12 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 88f0326c184a..501a55cecd73 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -237,6 +237,11 @@ enum x86_intercept_stage;
KVM_GUESTDBG_INJECT_DB | \
KVM_GUESTDBG_BLOCKIRQ)
+enum ap_reset_hold_type {
+ AP_RESET_HOLD_NONE,
+ AP_RESET_HOLD_NAE_EVENT,
+ AP_RESET_HOLD_MSR_PROTO,
+};
#define PFERR_PRESENT_BIT 0
#define PFERR_WRITE_BIT 1
@@ -908,6 +913,8 @@ struct kvm_vcpu_arch {
#if IS_ENABLED(CONFIG_HYPERV)
hpa_t hv_root_tdp;
#endif
+
+ enum ap_reset_hold_type reset_hold_type;
};
struct kvm_lpage_info {
@@ -1690,7 +1697,8 @@ int kvm_fast_pio(struct kvm_vcpu *vcpu, int size, unsigned short port, int in);
int kvm_emulate_cpuid(struct kvm_vcpu *vcpu);
int kvm_emulate_halt(struct kvm_vcpu *vcpu);
int kvm_vcpu_halt(struct kvm_vcpu *vcpu);
-int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu);
+int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu,
+ enum ap_reset_hold_type type);
int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu);
void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 159b22bb74e4..69653d7838e3 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2246,6 +2246,9 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
void sev_es_unmap_ghcb(struct vcpu_svm *svm)
{
+ /* Clear any indication that the vCPU is in a type of AP Reset Hold */
+ svm->vcpu.arch.reset_hold_type = AP_RESET_HOLD_NONE;
+
if (!svm->ghcb)
return;
@@ -2405,6 +2408,11 @@ static u64 ghcb_msr_version_info(void)
return msr;
}
+static u64 ghcb_msr_ap_rst_resp(u64 value)
+{
+ return (u64)GHCB_MSR_AP_RESET_HOLD_RESP | (value << GHCB_DATA_LOW);
+}
+
static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
{
struct vmcb_control_area *control = &svm->vmcb->control;
@@ -2451,6 +2459,16 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
break;
}
+ case GHCB_MSR_AP_RESET_HOLD_REQ:
+ ret = kvm_emulate_ap_reset_hold(&svm->vcpu, AP_RESET_HOLD_MSR_PROTO);
+
+ /*
+ * Preset the result to a non-SIPI return and then only set
+ * the result to non-zero when delivering a SIPI.
+ */
+ svm->vmcb->control.ghcb_gpa = ghcb_msr_ap_rst_resp(0);
+
+ break;
case GHCB_MSR_TERM_REQ: {
u64 reason_set, reason_code;
@@ -2536,7 +2554,7 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
ret = svm_invoke_exit_handler(vcpu, SVM_EXIT_IRET);
break;
case SVM_VMGEXIT_AP_HLT_LOOP:
- ret = kvm_emulate_ap_reset_hold(vcpu);
+ ret = kvm_emulate_ap_reset_hold(vcpu, AP_RESET_HOLD_NAE_EVENT);
break;
case SVM_VMGEXIT_AP_JUMP_TABLE: {
struct kvm_sev_info *sev = &to_kvm_svm(vcpu->kvm)->sev_info;
@@ -2671,13 +2689,23 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector)
return;
}
- /*
- * Subsequent SIPI: Return from an AP Reset Hold VMGEXIT, where
- * the guest will set the CS and RIP. Set SW_EXIT_INFO_2 to a
- * non-zero value.
- */
- if (!svm->ghcb)
- return;
-
- ghcb_set_sw_exit_info_2(svm->ghcb, 1);
+ /* Subsequent SIPI */
+ switch (vcpu->arch.reset_hold_type) {
+ case AP_RESET_HOLD_NAE_EVENT:
+ /*
+ * Return from an AP Reset Hold VMGEXIT, where the guest will
+ * set the CS and RIP. Set SW_EXIT_INFO_2 to a non-zero value.
+ */
+ ghcb_set_sw_exit_info_2(svm->ghcb, 1);
+ break;
+ case AP_RESET_HOLD_MSR_PROTO:
+ /*
+ * Return from an AP Reset Hold VMGEXIT, where the guest will
+ * set the CS and RIP. Set GHCB data field to a non-zero value.
+ */
+ svm->vmcb->control.ghcb_gpa = ghcb_msr_ap_rst_resp(1);
+ break;
+ default:
+ break;
+ }
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 46ee9bf61df4..1756511b873e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8672,10 +8672,13 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_emulate_halt);
-int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu)
+int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu,
+ enum ap_reset_hold_type type)
{
int ret = kvm_skip_emulated_instruction(vcpu);
+ vcpu->arch.reset_hold_type = type;
+
return __kvm_vcpu_halt(vcpu, KVM_MP_STATE_AP_RESET_HOLD, KVM_EXIT_AP_RESET_HOLD) && ret;
}
EXPORT_SYMBOL_GPL(kvm_emulate_ap_reset_hold);
--
2.33.0
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