Commit 95d9b5d8 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

Merge branch 'kvm-x86 mmio' 

Merge the MMIO stale data branch with the device posted IRQs branch to
provide a common base for removing KVM's tracking of "assigned" devices.

Link: https://lore.kernel.org/all/20250523011756.3243624-1-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parents 7e9b231c 83ebe715

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -1459,6 +1459,7 @@ struct kvm_arch { 
	bool x2apic_format;

	bool x2apic_broadcast_quirk_disabled;



	bool has_mapped_host_mmio;

	bool guest_can_read_msr_platform_info;

	bool exception_payload_enabled;

arch/x86/kvm/mmu/mmu_internal.h

+3 −0
Original line number Diff line number Diff line
@@ -103,6 +103,9 @@ struct kvm_mmu_page { 
		int root_count;

		refcount_t tdp_mmu_root_count;

	};



	bool has_mapped_host_mmio;



	union {

		/* These two members aren't used for TDP MMU */

		struct {

arch/x86/kvm/mmu/spte.c

+40 −3
Original line number Diff line number Diff line
@@ -104,7 +104,7 @@ u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access) 
	return spte;

}



static bool kvm_is_mmio_pfn(kvm_pfn_t pfn)

static bool __kvm_is_mmio_pfn(kvm_pfn_t pfn)

{

	if (pfn_valid(pfn))

		return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)) &&
@@ -125,6 +125,35 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) 
				     E820_TYPE_RAM);

}



static bool kvm_is_mmio_pfn(kvm_pfn_t pfn, int *is_host_mmio)

{

	/*

	 * Determining if a PFN is host MMIO is relative expensive.  Cache the

	 * result locally (in the sole caller) to avoid doing the full query

	 * multiple times when creating a single SPTE.

	 */

	if (*is_host_mmio < 0)

		*is_host_mmio = __kvm_is_mmio_pfn(pfn);



	return *is_host_mmio;

}



static void kvm_track_host_mmio_mapping(struct kvm_vcpu *vcpu)

{

	struct kvm_mmu_page *root = root_to_sp(vcpu->arch.mmu->root.hpa);



	if (root)

		WRITE_ONCE(root->has_mapped_host_mmio, true);

	else

		WRITE_ONCE(vcpu->kvm->arch.has_mapped_host_mmio, true);



	/*

	 * Force vCPUs to exit and flush CPU buffers if the vCPU is using the

	 * affected root(s).

	 */

	kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_OUTSIDE_GUEST_MODE);

}



/*

 * Returns true if the SPTE needs to be updated atomically due to having bits

 * that may be changed without holding mmu_lock, and for which KVM must not
@@ -162,6 +191,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, 
{

	int level = sp->role.level;

	u64 spte = SPTE_MMU_PRESENT_MASK;

	int is_host_mmio = -1;

	bool wrprot = false;



	/*
@@ -209,13 +239,15 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, 
	if (level > PG_LEVEL_4K)

		spte |= PT_PAGE_SIZE_MASK;



	spte |= kvm_x86_call(get_mt_mask)(vcpu, gfn, kvm_is_mmio_pfn(pfn));

	if (kvm_x86_ops.get_mt_mask)

		spte |= kvm_x86_call(get_mt_mask)(vcpu, gfn,

						  kvm_is_mmio_pfn(pfn, &is_host_mmio));

	if (host_writable)

		spte |= shadow_host_writable_mask;

	else

		pte_access &= ~ACC_WRITE_MASK;



	if (shadow_me_value && !kvm_is_mmio_pfn(pfn))

	if (shadow_me_value && !kvm_is_mmio_pfn(pfn, &is_host_mmio))

		spte |= shadow_me_value;



	spte |= (u64)pfn << PAGE_SHIFT;
@@ -260,6 +292,11 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, 
		mark_page_dirty_in_slot(vcpu->kvm, slot, gfn);

	}



	if (static_branch_unlikely(&cpu_buf_vm_clear) &&

	    !kvm_vcpu_can_access_host_mmio(vcpu) &&

	    kvm_is_mmio_pfn(pfn, &is_host_mmio))

		kvm_track_host_mmio_mapping(vcpu);



	*new_spte = spte;

	return wrprot;

}

arch/x86/kvm/mmu/spte.h

+10 −0
Original line number Diff line number Diff line
@@ -280,6 +280,16 @@ static inline bool is_mirror_sptep(tdp_ptep_t sptep) 
	return is_mirror_sp(sptep_to_sp(rcu_dereference(sptep)));

}



static inline bool kvm_vcpu_can_access_host_mmio(struct kvm_vcpu *vcpu)

{

	struct kvm_mmu_page *root = root_to_sp(vcpu->arch.mmu->root.hpa);



	if (root)

		return READ_ONCE(root->has_mapped_host_mmio);



	return READ_ONCE(vcpu->kvm->arch.has_mapped_host_mmio);

}



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

{

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

arch/x86/kvm/vmx/run_flags.h

+6 −4
Original line number Diff line number Diff line
@@ -4,8 +4,10 @@ 


#define VMX_RUN_VMRESUME_SHIFT				0

#define VMX_RUN_SAVE_SPEC_CTRL_SHIFT			1

#define VMX_RUN_CLEAR_CPU_BUFFERS_FOR_MMIO_SHIFT	2



#define VMX_RUN_VMRESUME			BIT(VMX_RUN_VMRESUME_SHIFT)

#define VMX_RUN_SAVE_SPEC_CTRL			BIT(VMX_RUN_SAVE_SPEC_CTRL_SHIFT)

#define VMX_RUN_CLEAR_CPU_BUFFERS_FOR_MMIO	BIT(VMX_RUN_CLEAR_CPU_BUFFERS_FOR_MMIO_SHIFT)



#endif /* __KVM_X86_VMX_RUN_FLAGS_H */