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From: Mahmoud Abumandour <ma.mandourr@gmail.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Mahmoud Abumandour <ma.mandourr@gmail.com>
Subject: [PATCH v2 0/2] KVM: nVMX: Don't let L2's LMSW modify CR0 bits owned by L1
Date: Thu, 29 Oct 2026 20:29:35 -0700	[thread overview]
Message-ID: <20261030032937.2813-1-ma.mandourr@gmail.com> (raw)

When L2's LMSW exits to L0 but not to L1, KVM emulates it with
kvm_lmsw(), which ignores vmcs12's CR0 guest/host mask, so L2 can change
CR0 bits that L1 owns.

v2:
 - Patch 2: order the CR0 store before FNOP and check L2's whole CR0.

v1: https://lore.kernel.org/all/20261029235040.12013-1-ma.mandourr@gmail.com

Mahmoud Abumandour (2):
  KVM: nVMX: Don't let L2's LMSW modify CR0 bits owned by L1
  KVM: selftests: Verify that L2's LMSW leaves L1-owned CR0 bits alone

 arch/x86/kvm/vmx/vmx.c                        | 15 ++++++++
 .../kvm/x86/nested_exceptions_test.c          | 36 +++++++++++++++++++
 2 files changed, 51 insertions(+)


base-commit: dea4f6380f4ec96e8f3b0aaf2343764bd0d25ef4
-- 
2.25.1


             reply	other threads:[~2026-10-30  3:29 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-30  3:29 Mahmoud Abumandour [this message]
2026-10-30  3:29 ` [PATCH v2 1/2] " Mahmoud Abumandour
2026-10-30  3:29 ` [PATCH v2 2/2] KVM: selftests: Verify that L2's LMSW leaves L1-owned CR0 bits alone Mahmoud Abumandour

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