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Message-Id: <20210713093546.7467-2-joro@8bytes.org>
Date: Tue, 13 Jul 2021 11:35:44 +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>,
Brijesh Singh <brijesh.singh@....com>,
Tom Lendacky <thomas.lendacky@....com>,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org, x86@...nel.org,
Joerg Roedel <jroedel@...e.de>
Subject: [PATCH 1/3] 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/sev-common.h | 1 +
arch/x86/kvm/svm/sev.c | 51 ++++++++++++++++++++++++++-----
arch/x86/kvm/svm/svm.h | 1 +
3 files changed, 45 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 2cef6c5a52c2..dda34ecac5c0 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -11,6 +11,7 @@
#define GHCB_MSR_INFO_POS 0
#define GHCB_DATA_LOW 12
#define GHCB_MSR_INFO_MASK (BIT_ULL(GHCB_DATA_LOW) - 1)
+#define GHCB_DATA_MASK GENMASK_ULL(51, 0)
#define GHCB_DATA(v) \
(((unsigned long)(v) & ~GHCB_MSR_INFO_MASK) >> GHCB_DATA_LOW)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 62926f1a5f7b..0ec88b349799 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -58,6 +58,10 @@ module_param_named(sev_es, sev_es_enabled, bool, 0444);
#define sev_es_enabled false
#endif /* CONFIG_KVM_AMD_SEV */
+#define AP_RESET_HOLD_NONE 0
+#define AP_RESET_HOLD_NAE_EVENT 1
+#define AP_RESET_HOLD_MSR_PROTO 2
+
static u8 sev_enc_bit;
static DECLARE_RWSEM(sev_deactivate_lock);
static DEFINE_MUTEX(sev_bitmap_lock);
@@ -2208,6 +2212,9 @@ 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->ap_reset_hold_type = AP_RESET_HOLD_NONE;
+
if (!svm->ghcb)
return;
@@ -2413,6 +2420,20 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
GHCB_MSR_INFO_POS);
break;
}
+ case GHCB_MSR_AP_RESET_HOLD_REQ: {
+ svm->ap_reset_hold_type = AP_RESET_HOLD_MSR_PROTO;
+ ret = kvm_emulate_ap_reset_hold(&svm->vcpu);
+
+ /*
+ * Preset the result to a non-SIPI return and then only set
+ * the result to non-zero when delivering a SIPI.
+ */
+ set_ghcb_msr_bits(svm, 0, GHCB_DATA_MASK, GHCB_DATA_LOW);
+
+ set_ghcb_msr_bits(svm, GHCB_MSR_AP_RESET_HOLD_RESP,
+ GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS);
+ break;
+ }
case GHCB_MSR_TERM_REQ: {
u64 reason_set, reason_code;
@@ -2500,6 +2521,7 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
ret = svm_invoke_exit_handler(vcpu, SVM_EXIT_IRET);
break;
case SVM_VMGEXIT_AP_HLT_LOOP:
+ svm->ap_reset_hold_type = AP_RESET_HOLD_NAE_EVENT;
ret = kvm_emulate_ap_reset_hold(vcpu);
break;
case SVM_VMGEXIT_AP_JUMP_TABLE: {
@@ -2637,13 +2659,26 @@ 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;
+ /* Subsequent SIPI */
+ switch (svm->ap_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.
+ */
+ set_ghcb_msr_bits(svm, 1, GHCB_DATA_MASK, GHCB_DATA_LOW);
- ghcb_set_sw_exit_info_2(svm->ghcb, 1);
+ set_ghcb_msr_bits(svm, GHCB_MSR_AP_RESET_HOLD_RESP,
+ GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS);
+ break;
+ default:
+ break;
+ }
}
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index f89b623bb591..b21b9df54121 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -187,6 +187,7 @@ struct vcpu_svm {
struct ghcb *ghcb;
struct kvm_host_map ghcb_map;
bool received_first_sipi;
+ unsigned int ap_reset_hold_type;
/* SEV-ES scratch area support */
void *ghcb_sa;
--
2.31.1
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