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Commit 85bb1e8b authored by Wei Wang's avatar Wei Wang Committed by Greg Kroah-Hartman
Browse files

svm: Add mutex_lock to protect apic_access_page_done on AMD systems 



commit 30510387a5e45bfcf8190e03ec7aa15b295828e2 upstream.

There is a race condition when accessing kvm->arch.apic_access_page_done.
Due to it, x86_set_memory_region will fail when creating the second vcpu
for a svm guest.

Add a mutex_lock to serialize the accesses to apic_access_page_done.
This lock is also used by vmx for the same purpose.

Signed-off-by: default avatarWei Wang <wawei@amazon.de>
Signed-off-by: default avatarAmadeusz Juskowiak <ajusk@amazon.de>
Signed-off-by: default avatarJulian Stecklina <jsteckli@amazon.de>
Signed-off-by: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: default avatarJoerg Roedel <jroedel@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e762e140

arch/x86/kvm/svm.c

+11 −8
Original line number Diff line number Diff line
@@ -1663,20 +1663,23 @@ static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu, 
static int avic_init_access_page(struct kvm_vcpu *vcpu)

{

	struct kvm *kvm = vcpu->kvm;

	int ret;

	int ret = 0;



	mutex_lock(&kvm->slots_lock);

	if (kvm->arch.apic_access_page_done)

		return 0;

		goto out;



	ret = x86_set_memory_region(kvm,

	ret = __x86_set_memory_region(kvm,

				      APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,

				      APIC_DEFAULT_PHYS_BASE,

				      PAGE_SIZE);

	if (ret)

		return ret;

		goto out;



	kvm->arch.apic_access_page_done = true;

	return 0;

out:

	mutex_unlock(&kvm->slots_lock);

	return ret;

}



static int avic_init_backing_page(struct kvm_vcpu *vcpu)