From:   isaku.yamahata@intel.com
To:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     isaku.yamahata@intel.com, isaku.yamahata@gmail.com,
        Paolo Bonzini <pbonzini@redhat.com>, erdemaktas@google.com,
        Sean Christopherson <seanjc@google.com>,
        Sagi Shahar <sagis@google.com>,
        David Matlack <dmatlack@google.com>,
        Kai Huang <kai.huang@intel.com>,
        Zhi Wang <zhi.wang.linux@gmail.com>
Subject: [PATCH v13 033/113] KVM: x86/mmu: Add Suppress VE bit to shadow_mmio_mask/shadow_present_mask
Date:   Sun, 12 Mar 2023 10:55:57 -0700
Message-Id: <8e5e50e4f21bcde0c3a8fb7a0b204ecab0c84cfa.1678643052.git.isaku.yamahata@intel.com>
In-Reply-To: <cover.1678643051.git.isaku.yamahata@intel.com>
References: <cover.1678643051.git.isaku.yamahata@intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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

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

TDX will require shadow_mmio_mask and shadow_present_mask to include
VMX_SUPPRESS_VE for shared GPA so that EPT violation is triggered for
shared GPA.  For VMX, VMX_SUPPRESS_VE doesn't matter for MMIO 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@intel.com>
---
 arch/x86/include/asm/vmx.h | 1 +
 arch/x86/kvm/mmu/spte.c    | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 498dc600bd5c..cdbf12c1a83c 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -511,6 +511,7 @@ enum vmcs_field {
 #define VMX_EPT_IPAT_BIT    			(1ull << 6)
 #define VMX_EPT_ACCESS_BIT			(1ull << 8)
 #define VMX_EPT_DIRTY_BIT			(1ull << 9)
+#define VMX_EPT_SUPPRESS_VE_BIT			(1ull << 63)
 #define VMX_EPT_RWX_MASK                        (VMX_EPT_READABLE_MASK |       \
 						 VMX_EPT_WRITABLE_MASK |       \
 						 VMX_EPT_EXECUTABLE_MASK)
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c
index c15bfca3ed15..41802e6d6f57 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