Sean Christopherson d97c0667c1 KVM: x86: Use __try_cmpxchg_user() to emulate atomic accesses
[ Upstream commit 1c2361f667f3648855ceae25f1332c18413fdb9f ]

Use the recently introduce __try_cmpxchg_user() to emulate atomic guest
accesses via the associated userspace address instead of mapping the
backing pfn into kernel address space.  Using kvm_vcpu_map() is unsafe as
it does not coordinate with KVM's mmu_notifier to ensure the hva=>pfn
translation isn't changed/unmapped in the memremap() path, i.e. when
there's no struct page and thus no elevated refcount.

Fixes: 42e35f8072c3 ("KVM/X86: Use kvm_vcpu_map in emulator_cmpxchg_emulated")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220202004945.2540433-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-07-29 17:25:26 +02:00
..
2022-07-12 16:35:02 +02:00
2022-07-23 12:54:14 +02:00