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Date: Wed, 7 Jul 2021 13:35:37 -0500
From: Brijesh Singh <brijesh.singh@....com>
To: x86@...nel.org, linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
linux-efi@...r.kernel.org, platform-driver-x86@...r.kernel.org,
linux-coco@...ts.linux.dev, linux-mm@...ck.org,
linux-crypto@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Joerg Roedel <jroedel@...e.de>,
Tom Lendacky <thomas.lendacky@....com>,
"H. Peter Anvin" <hpa@...or.com>, Ard Biesheuvel <ardb@...nel.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Andy Lutomirski <luto@...nel.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Sergio Lopez <slp@...hat.com>, Peter Gonda <pgonda@...gle.com>,
Peter Zijlstra <peterz@...radead.org>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
David Rientjes <rientjes@...gle.com>,
Dov Murik <dovmurik@...ux.ibm.com>,
Tobin Feldman-Fitzthum <tobin@....com>,
Borislav Petkov <bp@...en8.de>,
Michael Roth <michael.roth@....com>,
Vlastimil Babka <vbabka@...e.cz>, tony.luck@...el.com,
npmccallum@...hat.com, brijesh.ksingh@...il.com,
Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH Part2 RFC v4 01/40] 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>
---
arch/x86/include/asm/sev-common.h | 6 ++++
arch/x86/kvm/svm/sev.c | 56 ++++++++++++++++++++++++++-----
arch/x86/kvm/svm/svm.h | 1 +
3 files changed, 55 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index e14d24f0950c..466baa9cd0f5 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -45,6 +45,12 @@
(((unsigned long)reg & GHCB_MSR_CPUID_REG_MASK) << GHCB_MSR_CPUID_REG_POS) | \
(((unsigned long)fn) << GHCB_MSR_CPUID_FUNC_POS))
+/* AP Reset Hold */
+#define GHCB_MSR_AP_RESET_HOLD_REQ 0x006
+#define GHCB_MSR_AP_RESET_HOLD_RESP 0x007
+#define GHCB_MSR_AP_RESET_HOLD_RESULT_POS 12
+#define GHCB_MSR_AP_RESET_HOLD_RESULT_MASK GENMASK_ULL(51, 0)
+
/* GHCB GPA Register */
#define GHCB_MSR_GPA_REG_REQ 0x012
#define GHCB_MSR_GPA_REG_VALUE_POS 12
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index d93a1c368b61..7d0b98dbe523 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -57,6 +57,10 @@ 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);
@@ -2199,6 +2203,9 @@ 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;
@@ -2404,6 +2411,22 @@ 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_MSR_AP_RESET_HOLD_RESULT_MASK,
+ GHCB_MSR_AP_RESET_HOLD_RESULT_POS);
+
+ 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;
@@ -2491,6 +2514,7 @@ 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: {
@@ -2628,13 +2652,29 @@ 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_MSR_AP_RESET_HOLD_RESULT_MASK,
+ GHCB_MSR_AP_RESET_HOLD_RESULT_POS);
- 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 0b89aee51b74..ad12ca26b2d8 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -174,6 +174,7 @@ 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;
--
2.17.1
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