[PATCH v2 2/2] Revert "KVM: x86: work around leak of uninitialized stack contents"

[Vitaly Kuznetsov]

handle_vmptrst()/handle_vmread() stopped injecting #PF unconditionally
and switched to nested_vmx_handle_memory_failure() which just kills the
guest with KVM_EXIT_INTERNAL_ERROR in case of MMIO access, zeroing
'exception' in kvm_write_guest_virt_system() is not needed anymore.

This reverts commit 541ab2aeb28251bf7135c7961f3a6080eebcc705.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
 arch/x86/kvm/x86.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9e41b5135340..0097a97d331f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5647,13 +5647,6 @@ int kvm_write_guest_virt_system(struct kvm_vcpu *vcpu, gva_t addr, void *val,
 	/* kvm_write_guest_virt_system can pull in tons of pages. */
 	vcpu->arch.l1tf_flush_l1d = true;
 
-	/*
-	 * FIXME: this should call handle_emulation_failure if X86EMUL_IO_NEEDED
-	 * is returned, but our callers are not ready for that and they blindly
-	 * call kvm_inject_page_fault.  Ensure that they at least do not leak
-	 * uninitialized kernel stack memory into cr2 and error code.
-	 */
-	memset(exception, 0, sizeof(*exception));
 	return kvm_write_guest_virt_helper(addr, val, bytes, vcpu,
 					   PFERR_WRITE_MASK, exception);
 }
-- 
2.25.4