Commit 6961ab0b authored by Isaku Yamahata's avatar Isaku Yamahata Committed by Paolo Bonzini
Browse files

KVM: x86/mmu: Add an is_mirror member for union kvm_mmu_page_role 



Introduce a "is_mirror" member to the kvm_mmu_page_role union to identify
SPTEs associated with the mirrored EPT.

The TDX module maintains the private half of the EPT mapped in the TD in
its protected memory. KVM keeps a copy of the private GPAs in a mirrored
EPT tree within host memory. This "is_mirror" attribute enables vCPUs to
find and get the root page of mirrored EPT from the MMU root list for a
guest TD. This also allows KVM MMU code to detect changes in mirrored EPT
according to the "is_mirror" mmu page role and propagate the changes to
the private EPT managed by TDX module.

Signed-off-by: default avatarIsaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: default avatarRick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-6-rick.p.edgecombe@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3a4eb364

arch/x86/include/asm/kvm_host.h

+5 −3
Original line number Diff line number Diff line
@@ -313,10 +313,11 @@ struct kvm_kernel_irq_routing_entry; 
 * the number of unique SPs that can theoretically be created is 2^n, where n

 * is the number of bits that are used to compute the role.

 *

 * But, even though there are 19 bits in the mask below, not all combinations

 * But, even though there are 20 bits in the mask below, not all combinations

 * of modes and flags are possible:

 *

 *   - invalid shadow pages are not accounted, so the bits are effectively 18

 *   - invalid shadow pages are not accounted, mirror pages are not shadowed,

 *     so the bits are effectively 18.

 *

 *   - quadrant will only be used if has_4_byte_gpte=1 (non-PAE paging);

 *     execonly and ad_disabled are only used for nested EPT which has
@@ -349,7 +350,8 @@ union kvm_mmu_page_role { 
		unsigned ad_disabled:1;

		unsigned guest_mode:1;

		unsigned passthrough:1;

		unsigned :5;

		unsigned is_mirror:1;

		unsigned :4;



		/*

		 * This is left at the top of the word so that

arch/x86/kvm/mmu/mmu_internal.h

+5 −0
Original line number Diff line number Diff line
@@ -157,6 +157,11 @@ static inline int kvm_mmu_page_as_id(struct kvm_mmu_page *sp) 
	return kvm_mmu_role_as_id(sp->role);

}



static inline bool is_mirror_sp(const struct kvm_mmu_page *sp)

{

	return sp->role.is_mirror;

}



static inline void kvm_mmu_alloc_external_spt(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)

{

	/*

arch/x86/kvm/mmu/spte.h

+5 −0
Original line number Diff line number Diff line
@@ -276,6 +276,11 @@ static inline struct kvm_mmu_page *root_to_sp(hpa_t root) 
	return spte_to_child_sp(root);

}



static inline bool is_mirror_sptep(tdp_ptep_t sptep)

{

	return is_mirror_sp(sptep_to_sp(rcu_dereference(sptep)));

}



static inline bool is_mmio_spte(struct kvm *kvm, u64 spte)

{

	return (spte & shadow_mmio_mask) == kvm->arch.shadow_mmio_value &&