linux-kernel - [PATCH 16/24] KVM: x86/mmu: Co-locate code for setting various SPTE masks

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Date:   Thu, 25 Feb 2021 12:47:41 -0800
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Ben Gardon <bgardon@...gle.com>
Subject: [PATCH 16/24] KVM: x86/mmu: Co-locate code for setting various SPTE masks

Squish all the code for (re)setting the various SPTE masks into one
location.  With the split code, it's not at all clear that the masks are
set once during module initialization.  This will allow a future patch to
clean up initialization of the masks without shuffling code all over
tarnation.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c  | 25 -------------------------
 arch/x86/kvm/mmu/spte.c | 19 +++++++++++++++++++
 arch/x86/kvm/vmx/vmx.c  | 17 ++++++-----------
 3 files changed, 25 insertions(+), 36 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 99d9c85a1820..1fb500db46e0 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5710,25 +5710,6 @@ static void mmu_destroy_caches(void)
 	kmem_cache_destroy(mmu_page_header_cache);
 }
 
-static void kvm_set_mmio_spte_mask(void)
-{
-	u64 mask;
-
-	/*
-	 * Set a reserved PA bit in MMIO SPTEs to generate page faults with
-	 * PFEC.RSVD=1 on MMIO accesses.  64-bit PTEs (PAE, x86-64, and EPT
-	 * paging) support a maximum of 52 bits of PA, i.e. if the CPU supports
-	 * 52-bit physical addresses then there are no reserved PA bits in the
-	 * PTEs and so the reserved PA approach must be disabled.
-	 */
-	if (shadow_phys_bits < 52)
-		mask = BIT_ULL(51) | PT_PRESENT_MASK;
-	else
-		mask = 0;
-
-	kvm_mmu_set_mmio_spte_mask(mask, mask, ACC_WRITE_MASK | ACC_USER_MASK);
-}
-
 static bool get_nx_auto_mode(void)
 {
 	/* Return true when CPU has the bug, and mitigations are ON */
@@ -5794,12 +5775,6 @@ int kvm_mmu_module_init(void)
 
 	kvm_mmu_reset_all_pte_masks();
 
-	kvm_set_mmio_spte_mask();
-
-	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
-			PT_DIRTY_MASK, PT64_NX_MASK, 0,
-			PT_PRESENT_MASK, 0, sme_me_mask);
-
 	pte_list_desc_cache = kmem_cache_create("pte_list_desc",
 					    sizeof(struct pte_list_desc),
 					    0, SLAB_ACCOUNT, NULL);
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c
index cf0e20b34cd3..b15d6006dbee 100644
--- a/arch/x86/kvm/mmu/spte.c
+++ b/arch/x86/kvm/mmu/spte.c
@@ -310,6 +310,7 @@ EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
 void kvm_mmu_reset_all_pte_masks(void)
 {
 	u8 low_phys_bits;
+	u64 mask;
 
 	shadow_user_mask = 0;
 	shadow_accessed_mask = 0;
@@ -344,4 +345,22 @@ void kvm_mmu_reset_all_pte_masks(void)
 
 	shadow_nonpresent_or_rsvd_lower_gfn_mask =
 		GENMASK_ULL(low_phys_bits - 1, PAGE_SHIFT);
+
+	/*
+	 * Set a reserved PA bit in MMIO SPTEs to generate page faults with
+	 * PFEC.RSVD=1 on MMIO accesses.  64-bit PTEs (PAE, x86-64, and EPT
+	 * paging) support a maximum of 52 bits of PA, i.e. if the CPU supports
+	 * 52-bit physical addresses then there are no reserved PA bits in the
+	 * PTEs and so the reserved PA approach must be disabled.
+	 */
+	if (shadow_phys_bits < 52)
+		mask = BIT_ULL(51) | PT_PRESENT_MASK;
+	else
+		mask = 0;
+
+	kvm_mmu_set_mmio_spte_mask(mask, mask, ACC_WRITE_MASK | ACC_USER_MASK);
+
+	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
+			PT_DIRTY_MASK, PT64_NX_MASK, 0,
+			PT_PRESENT_MASK, 0, sme_me_mask);
 }
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 8a8423a97f13..730076b3832f 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4314,16 +4314,6 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
 	vmx->secondary_exec_control = exec_control;
 }
 
-static void ept_set_mmio_spte_mask(void)
-{
-	/*
-	 * EPT Misconfigurations can be generated if the value of bits 2:0
-	 * 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);
-}
-
 #define VMX_XSS_EXIT_BITMAP 0
 
 /*
@@ -5462,7 +5452,12 @@ static void vmx_enable_tdp(void)
 		cpu_has_vmx_ept_execute_only() ? 0ull : VMX_EPT_READABLE_MASK,
 		VMX_EPT_RWX_MASK, 0ull);
 
-	ept_set_mmio_spte_mask();
+	/*
+	 * EPT Misconfigurations can be generated if the value of bits 2:0
+	 * 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);
 }
 
 /*
-- 
2.30.1.766.gb4fecdf3b7-goog