linux-kernel - [PATCH 02/10] KVM: SVM: Use AVIC_HPA_MASK when initializing vCPU's Physical ID entry

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Message-ID: <20230815213533.548732-3-seanjc@google.com>
Date:   Tue, 15 Aug 2023 14:35:25 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Joerg Roedel <joro@...tes.org>
Cc:     kvm@...r.kernel.org, iommu@...ts.linux.dev,
        linux-kernel@...r.kernel.org, Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 02/10] KVM: SVM: Use AVIC_HPA_MASK when initializing vCPU's
 Physical ID entry

Use AVIC_HPA_MASK instead of AVIC_PHYSICAL_ID_ENTRY_BACKING_PAGE_MASK when
initializing a vCPU's Physical ID table entry, the two masks are identical.
Keep both #defines for now, along with a few new static asserts.  A future
change will clean up the entire mess (spoiler alert, the masks are
pointless).

Opportunisitically move the bitwise-OR of AVIC_PHYSICAL_ID_ENTRY_VALID_MASK
outside of the call to __sme_set(), again to pave the way for code
deduplication.  __sme_set() is purely additive, i.e. ORing in the valid
bit before or after the C-bit does not change the end result.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/include/asm/svm.h | 2 ++
 arch/x86/kvm/svm/avic.c    | 5 ++---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 1e70600e84f7..609c9b596399 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -285,6 +285,8 @@ static_assert((AVIC_MAX_PHYSICAL_ID & AVIC_PHYSICAL_MAX_INDEX_MASK) == AVIC_MAX_
 static_assert((X2AVIC_MAX_PHYSICAL_ID & AVIC_PHYSICAL_MAX_INDEX_MASK) == X2AVIC_MAX_PHYSICAL_ID);
 
 #define AVIC_HPA_MASK	~((0xFFFULL << 52) | 0xFFF)
+static_assert(AVIC_PHYSICAL_ID_ENTRY_BACKING_PAGE_MASK == AVIC_HPA_MASK);
+static_assert(AVIC_PHYSICAL_ID_ENTRY_BACKING_PAGE_MASK == GENMASK_ULL(51, 12));
 
 #define SVM_SEV_FEAT_DEBUG_SWAP                        BIT(5)
 
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 7062164e4041..442c58ef8158 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -308,9 +308,8 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu)
 	if (!entry)
 		return -EINVAL;
 
-	new_entry = __sme_set((page_to_phys(svm->avic_backing_page) &
-			      AVIC_PHYSICAL_ID_ENTRY_BACKING_PAGE_MASK) |
-			      AVIC_PHYSICAL_ID_ENTRY_VALID_MASK);
+	new_entry = __sme_set(page_to_phys(svm->avic_backing_page) & AVIC_HPA_MASK) |
+		    AVIC_PHYSICAL_ID_ENTRY_VALID_MASK;
 	WRITE_ONCE(*entry, new_entry);
 
 	svm->avic_physical_id_cache = entry;
-- 
2.41.0.694.ge786442a9b-goog