linux-kernel - [PATCH v11 032/113] KVM: x86/mmu: Add Suppress VE bit to shadow_mmio

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Message-Id: <8cb87ec35b24d9cf5b47b650597c3005a8adf247.1673539699.git.isaku.yamahata@intel.com>
Date:   Thu, 12 Jan 2023 08:31:40 -0800
From:   isaku.yamahata@...el.com
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Paolo Bonzini <pbonzini@...hat.com>, erdemaktas@...gle.com,
        Sean Christopherson <seanjc@...gle.com>,
        Sagi Shahar <sagis@...gle.com>,
        David Matlack <dmatlack@...gle.com>
Subject: [PATCH v11 032/113] KVM: x86/mmu: Add Suppress VE bit to shadow_mmio_mask

From: Isaku Yamahata <isaku.yamahata@...el.com>

To make use of the same value of shadow_mmio_mask for TDX and VMX, add
Suppress-VE bit to shadow_mmio_mask so that shadow_mmio_mask can be common
for both VMX and TDX.

TDX will need shadow_mmio_mask to be VMX_SUPPRESS_VE | RWX and
shadow_mmio_value to be 0 so that EPT violation is triggered.  For VMX,
VMX_SUPPRESS_VE doesn't matter because the spte value is required to cause
EPT misconfig.  the additional bit doesn't affect VMX logic to add the bit
to shadow_mmio_{value, mask}.

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
 arch/x86/kvm/mmu/spte.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c
index fce6f047399f..cc0bc058fb25 100644
--- a/arch/x86/kvm/mmu/spte.c
+++ b/arch/x86/kvm/mmu/spte.c
@@ -431,7 +431,9 @@ void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only)
 	shadow_dirty_mask	= has_ad_bits ? VMX_EPT_DIRTY_BIT : 0ull;
 	shadow_nx_mask		= 0ull;
 	shadow_x_mask		= VMX_EPT_EXECUTABLE_MASK;
-	shadow_present_mask	= has_exec_only ? 0ull : VMX_EPT_READABLE_MASK;
+	/* VMX_EPT_SUPPRESS_VE_BIT is needed for W or X violation. */
+	shadow_present_mask	=
+		(has_exec_only ? 0ull : VMX_EPT_READABLE_MASK) | VMX_EPT_SUPPRESS_VE_BIT;
 	/*
 	 * EPT overrides the host MTRRs, and so KVM must program the desired
 	 * memtype directly into the SPTEs.  Note, this mask is just the mask
@@ -448,7 +450,7 @@ void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only)
 	 * of an EPT paging-structure entry is 110b (write/execute).
 	 */
 	kvm_mmu_set_mmio_spte_mask(VMX_EPT_MISCONFIG_WX_VALUE,
-				   VMX_EPT_RWX_MASK, 0);
+				   VMX_EPT_RWX_MASK | VMX_EPT_SUPPRESS_VE_BIT, 0);
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_set_ept_masks);
 
-- 
2.25.1