Commit 38bf9d7b authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86/mmu: Add shadow mask for effective host MTRR memtype 



Add shadow_memtype_mask to capture that EPT needs a non-zero memtype mask
instead of relying on TDP being enabled, as NPT doesn't need a non-zero
mask.  This is a glorified nop as kvm_x86_ops.get_mt_mask() returns zero
for NPT anyways.

No functional change intended.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220715230016.3762909-4-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 82ffad2d

arch/x86/kvm/mmu/spte.c

+18 −3
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ u64 __read_mostly shadow_mmio_value; 
u64 __read_mostly shadow_mmio_mask;

u64 __read_mostly shadow_mmio_access_mask;

u64 __read_mostly shadow_present_mask;

u64 __read_mostly shadow_memtype_mask;

u64 __read_mostly shadow_me_value;

u64 __read_mostly shadow_me_mask;

u64 __read_mostly shadow_acc_track_mask;
@@ -161,10 +162,10 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, 


	if (level > PG_LEVEL_4K)

		spte |= PT_PAGE_SIZE_MASK;

	if (tdp_enabled)



	if (shadow_memtype_mask)

		spte |= static_call(kvm_x86_get_mt_mask)(vcpu, gfn,

							 kvm_is_mmio_pfn(pfn));



	if (host_writable)

		spte |= shadow_host_writable_mask;

	else
@@ -391,6 +392,13 @@ void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only) 
	shadow_nx_mask		= 0ull;

	shadow_x_mask		= VMX_EPT_EXECUTABLE_MASK;

	shadow_present_mask	= has_exec_only ? 0ull : VMX_EPT_READABLE_MASK;

	/*

	 * EPT overrides the host MTRRs, and so KVM must program the desired

	 * memtype directly into the SPTEs.  Note, this mask is just the mask

	 * of all bits that factor into the memtype, the actual memtype must be

	 * dynamically calculated, e.g. to ensure host MMIO is mapped UC.

	 */

	shadow_memtype_mask	= VMX_EPT_MT_MASK | VMX_EPT_IPAT_BIT;

	shadow_acc_track_mask	= VMX_EPT_RWX_MASK;

	shadow_host_writable_mask = EPT_SPTE_HOST_WRITABLE;

	shadow_mmu_writable_mask  = EPT_SPTE_MMU_WRITABLE;
@@ -441,6 +449,13 @@ void kvm_mmu_reset_all_pte_masks(void) 
	shadow_nx_mask		= PT64_NX_MASK;

	shadow_x_mask		= 0;

	shadow_present_mask	= PT_PRESENT_MASK;



	/*

	 * For shadow paging and NPT, KVM uses PAT entry '0' to encode WB

	 * memtype in the SPTEs, i.e. relies on host MTRRs to provide the

	 * correct memtype (WB is the "weakest" memtype).

	 */

	shadow_memtype_mask	= 0;

	shadow_acc_track_mask	= 0;

	shadow_me_mask		= 0;

	shadow_me_value		= 0;

arch/x86/kvm/mmu/spte.h

+1 −0
Original line number Diff line number Diff line
@@ -147,6 +147,7 @@ extern u64 __read_mostly shadow_mmio_value; 
extern u64 __read_mostly shadow_mmio_mask;

extern u64 __read_mostly shadow_mmio_access_mask;

extern u64 __read_mostly shadow_present_mask;

extern u64 __read_mostly shadow_memtype_mask;

extern u64 __read_mostly shadow_me_value;

extern u64 __read_mostly shadow_me_mask;