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From: Kenta Akagi <k@mgml.me>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	stable@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Lai Jiangshan <laijs@linux.alibaba.com>, Kenta Akagi <k@mgml.me>
Subject: [PATCH 5.15.y v4 05/11] KVM: X86: Calculate quadrant when !role.gpte_is_8_bytes
Date: Tue, 29 Sep 2026 01:44:21 +0900	[thread overview]
Message-ID: <20260928164427.4699-6-k@mgml.me> (raw)
In-Reply-To: <20260928164427.4699-1-k@mgml.me>

From: Lai Jiangshan <laijs@linux.alibaba.com>

commit b46a13cb7ea1137b2e01dfaafcacd5cd79db8390 upstream.

role.quadrant is only valid when gpte size is 4 bytes and only be
calculated when gpte size is 4 bytes.

Although "vcpu->arch.mmu->root_level <= PT32_ROOT_LEVEL" also means
gpte size is 4 bytes, but using "!role.gpte_is_8_bytes" is clearer

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211118110814.2568-15-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kenta Akagi <k@mgml.me>
---
 arch/x86/kvm/mmu/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f6ad81b5e637..62e9a7db0183 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2094,7 +2094,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 	role.level = level;
 	role.direct = direct;
 	role.access = access;
-	if (!direct_mmu && vcpu->arch.mmu->root_level <= PT32_ROOT_LEVEL) {
+	if (!direct_mmu && !role.gpte_is_8_bytes) {
 		quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
 		quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
 		role.quadrant = quadrant;
-- 
2.53.0


  parent reply	other threads:[~2026-09-28 16:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-28 16:44 [PATCH 5.15.y v4 00/11] KVM: fixes for CVE-2026-46113 and related issues Kenta Akagi
2026-09-28 16:44 ` [PATCH 5.15.y v4 01/11] KVM: x86/mmu: Use a bool for direct Kenta Akagi
2026-09-28 16:44 ` [PATCH 5.15.y v4 02/11] KVM: x86/mmu: Stop passing "direct" to mmu_alloc_root() Kenta Akagi
2026-09-28 16:44 ` [PATCH 5.15.y v4 03/11] KVM: MMU: update comment on the number of page role combinations Kenta Akagi
2026-09-28 16:52   ` sashiko-bot
2026-09-28 16:44 ` [PATCH 5.15.y v4 04/11] KVM: X86: Remove useless code to set role.gpte_is_8_bytes when role.direct Kenta Akagi
2026-09-28 16:44 ` Kenta Akagi [this message]
2026-09-28 16:44 ` [PATCH 5.15.y v4 06/11] KVM: X86: Rename gpte_is_8_bytes to has_4_byte_gpte and invert the direction Kenta Akagi
2026-09-28 16:55   ` sashiko-bot
2026-09-28 16:44 ` [PATCH 5.15.y v4 07/11] KVM: x86/mmu: Derive shadow MMU page role from parent Kenta Akagi
2026-09-28 16:44 ` [PATCH 5.15.y v4 08/11] KVM: x86/mmu: Always pass 0 for @quadrant when gptes are 8 bytes Kenta Akagi
2026-09-28 16:44 ` [PATCH 5.15.y v4 09/11] KVM: x86/mmu: pull call to drop_large_spte() into __link_shadow_page() Kenta Akagi
2026-09-28 16:44 ` [PATCH 5.15.y v4 10/11] KVM: x86: Fix shadow paging use-after-free due to unexpected GFN Kenta Akagi
2026-09-28 16:44 ` [PATCH 5.15.y v4 11/11] KVM: x86: Fix shadow paging use-after-free due to unexpected role Kenta Akagi
2026-09-28 18:28 ` [PATCH 5.15.y v4 00/11] KVM: fixes for CVE-2026-46113 and related issues Sean Christopherson
2026-09-28 22:39 ` Sasha Levin

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