Commit a90764f0 authored by Michael Roth's avatar Michael Roth Committed by Paolo Bonzini
Browse files

KVM: guest_memfd: Add hook for invalidating memory 



In some cases, like with SEV-SNP, guest memory needs to be updated in a
platform-specific manner before it can be safely freed back to the host.
Wire up arch-defined hooks to the .free_folio kvm_gmem_aops callback to
allow for special handling of this sort when freeing memory in response
to FALLOC_FL_PUNCH_HOLE operations and when releasing the inode, and go
ahead and define an arch-specific hook for x86 since it will be needed
for handling memory used for SEV-SNP guests.

Signed-off-by: default avatarMichael Roth <michael.roth@amd.com>
Message-Id: <20231230172351.574091-6-michael.roth@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1f6c06b1

arch/x86/include/asm/kvm-x86-ops.h

+1 −0
Original line number Diff line number Diff line
@@ -140,6 +140,7 @@ KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons); 
KVM_X86_OP_OPTIONAL(get_untagged_addr)

KVM_X86_OP_OPTIONAL(alloc_apic_backing_page)

KVM_X86_OP_OPTIONAL_RET0(gmem_prepare)

KVM_X86_OP_OPTIONAL(gmem_invalidate)



#undef KVM_X86_OP

#undef KVM_X86_OP_OPTIONAL

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -1813,6 +1813,7 @@ struct kvm_x86_ops { 
	gva_t (*get_untagged_addr)(struct kvm_vcpu *vcpu, gva_t gva, unsigned int flags);

	void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu);

	int (*gmem_prepare)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order);

	void (*gmem_invalidate)(kvm_pfn_t start, kvm_pfn_t end);

};



struct kvm_x86_nested_ops {

arch/x86/kvm/x86.c

+7 −0
Original line number Diff line number Diff line
@@ -13605,6 +13605,13 @@ int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_ord 
}

#endif



#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE

void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end)

{

	static_call_cond(kvm_x86_gmem_invalidate)(start, end);

}

#endif



int kvm_spec_ctrl_test_value(u64 value)

{

	/*

include/linux/kvm_host.h

+4 −0
Original line number Diff line number Diff line
@@ -2475,4 +2475,8 @@ typedef int (*kvm_gmem_populate_cb)(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, 
long kvm_gmem_populate(struct kvm *kvm, gfn_t gfn, void __user *src, long npages,

		       kvm_gmem_populate_cb post_populate, void *opaque);



#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE

void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end);

#endif



#endif

virt/kvm/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -113,3 +113,7 @@ config KVM_GENERIC_PRIVATE_MEM 
config HAVE_KVM_GMEM_PREPARE

       bool

       depends on KVM_PRIVATE_MEM



config HAVE_KVM_GMEM_INVALIDATE

       bool

       depends on KVM_PRIVATE_MEM