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svm: Add mutex_lock to protect apic_access_page_done on AMD systems 

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: Wei Wang <wawei@amazon.de>
Signed-off-by: Amadeusz Juskowiak <ajusk@amazon.de>
Signed-off-by: Julian Stecklina <jsteckli@amazon.de>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hifive-unleashed-5.1
Wei Wang 2018-11-12 12:23:14 +00:00 committed by Paolo Bonzini
parent e97f852fd4
commit 30510387a5
1 changed files with 11 additions and 8 deletions
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19
arch/x86/kvm/svm.c
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@ -1664,20 +1664,23 @@ 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,
APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,
APIC_DEFAULT_PHYS_BASE,
PAGE_SIZE);
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)