linux-kernel - [PATCH v3 2/3] KVM: SVM: remove uneeded fields from host_save_users

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Message-Id: <20210105143749.557054-3-michael.roth@amd.com>
Date:   Tue,  5 Jan 2021 08:37:49 -0600
From:   Michael Roth <michael.roth@....com>
To:     kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Andy Lutomirski <luto@...capital.net>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H . Peter Anvin" <hpa@...or.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v3 2/3] KVM: SVM: remove uneeded fields from host_save_users_msrs

Now that the set of host user MSRs that need to be individually
saved/restored are the same with/without SEV-ES, we can drop the
.sev_es_restored flag and just iterate through the list unconditionally
for both cases. A subsequent patch can then move these loops to a
common path.

Signed-off-by: Michael Roth <michael.roth@....com>
---
 arch/x86/kvm/svm/sev.c | 16 ++++------------
 arch/x86/kvm/svm/svm.c |  6 ++----
 arch/x86/kvm/svm/svm.h |  7 ++-----
 3 files changed, 8 insertions(+), 21 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index e57847ff8bd2..2a93b63322f4 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2007,12 +2007,8 @@ void sev_es_vcpu_load(struct vcpu_svm *svm, int cpu)
 	 * Certain MSRs are restored on VMEXIT, only save ones that aren't
 	 * restored.
 	 */
-	for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) {
-		if (host_save_user_msrs[i].sev_es_restored)
-			continue;
-
-		rdmsrl(host_save_user_msrs[i].index, svm->host_user_msrs[i]);
-	}
+	for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
+		rdmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
 
 	/* XCR0 is restored on VMEXIT, save the current host value */
 	hostsa = (struct vmcb_save_area *)(page_address(sd->save_area) + 0x400);
@@ -2033,10 +2029,6 @@ void sev_es_vcpu_put(struct vcpu_svm *svm)
 	 * Certain MSRs are restored on VMEXIT and were saved with vmsave in
 	 * sev_es_vcpu_load() above. Only restore ones that weren't.
 	 */
-	for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) {
-		if (host_save_user_msrs[i].sev_es_restored)
-			continue;
-
-		wrmsrl(host_save_user_msrs[i].index, svm->host_user_msrs[i]);
-	}
+	for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
+		wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
 }
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 7a7e9b7d47a7..7e1b5b452244 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1421,8 +1421,7 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		sev_es_vcpu_load(svm, cpu);
 	} else {
 		for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
-			rdmsrl(host_save_user_msrs[i].index,
-			       svm->host_user_msrs[i]);
+			rdmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
 
 		asm volatile(__ex("vmsave %%"_ASM_AX)
 			     : : "a" (page_to_phys(sd->save_area)) : "memory");
@@ -1458,8 +1457,7 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
 		sev_es_vcpu_put(svm);
 	} else {
 		for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
-			wrmsrl(host_save_user_msrs[i].index,
-			       svm->host_user_msrs[i]);
+			wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
 	}
 }
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 1f4460508036..a476449862f8 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -23,11 +23,8 @@
 
 #define __sme_page_pa(x) __sme_set(page_to_pfn(x) << PAGE_SHIFT)
 
-static const struct svm_host_save_msrs {
-	u32 index;		/* Index of the MSR */
-	bool sev_es_restored;	/* True if MSR is restored on SEV-ES VMEXIT */
-} host_save_user_msrs[] = {
-	{ .index = MSR_TSC_AUX,			.sev_es_restored = false },
+static const u32 host_save_user_msrs[] = {
+	MSR_TSC_AUX,
 };
 #define NR_HOST_SAVE_USER_MSRS ARRAY_SIZE(host_save_user_msrs)
 
-- 
2.25.1