linux-kernel - [PATCH Part2 RFC v4 39/40] KVM: SVM: Use a VMSA physical address variable for populating VMCB

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Date:   Wed,  7 Jul 2021 13:36:15 -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 39/40] KVM: SVM: Use a VMSA physical address variable for populating VMCB

From: Tom Lendacky <thomas.lendacky@....com>

In preparation to support SEV-SNP AP Creation, use a variable that holds
the VMSA physical address rather than converting the virtual address.
This will allow SEV-SNP AP Creation to set the new physical address that
will be used should the vCPU reset path be taken.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
---
 arch/x86/kvm/svm/sev.c | 5 ++---
 arch/x86/kvm/svm/svm.c | 9 ++++++++-
 arch/x86/kvm/svm/svm.h | 1 +
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 4cb4c1d7e444..d8ad6dd58c87 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3553,10 +3553,9 @@ void sev_es_init_vmcb(struct vcpu_svm *svm)
 
 	/*
 	 * An SEV-ES guest requires a VMSA area that is a separate from the
-	 * VMCB page. Do not include the encryption mask on the VMSA physical
-	 * address since hardware will access it using the guest key.
+	 * VMCB page.
 	 */
-	svm->vmcb->control.vmsa_pa = __pa(svm->vmsa);
+	svm->vmcb->control.vmsa_pa = svm->vmsa_pa;
 
 	/* Can't intercept CR register access, HV can't modify CR registers */
 	svm_clr_intercept(svm, INTERCEPT_CR0_READ);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 32e35d396508..74bc635c9608 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1379,9 +1379,16 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
 	svm->vmcb01.ptr = page_address(vmcb01_page);
 	svm->vmcb01.pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT);
 
-	if (vmsa_page)
+	if (vmsa_page) {
 		svm->vmsa = page_address(vmsa_page);
 
+		/*
+		 * Do not include the encryption mask on the VMSA physical
+		 * address since hardware will access it using the guest key.
+		 */
+		svm->vmsa_pa = __pa(svm->vmsa);
+	}
+
 	svm->guest_state_loaded = false;
 
 	svm_switch_vmcb(svm, &svm->vmcb01);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 9fcfc0a51737..285d9b97b4d2 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -177,6 +177,7 @@ struct vcpu_svm {
 
 	/* SEV-ES support */
 	struct sev_es_save_area *vmsa;
+	hpa_t vmsa_pa;
 	struct ghcb *ghcb;
 	struct kvm_host_map ghcb_map;
 	bool received_first_sipi;
-- 
2.17.1