linux-kernel - [PATCH 2/2] selftests: kvm/set_memory_region_test: do not check RIP if the guest shuts down

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 17 Apr 2020 12:38:43 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>
Subject: [PATCH 2/2] selftests: kvm/set_memory_region_test: do not check RIP if the guest shuts down

On AMD, the state of the VMCB is undefined after a shutdown VMEXIT.  KVM
takes a very conservative approach to that and resets the guest altogether
when that happens.  This causes the set_memory_region_test to fail
because the RIP is 0xfff0 (the reset vector).  Restrict the RIP test
to KVM_EXIT_INTERNAL_ERROR in order to fix this.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 .../testing/selftests/kvm/set_memory_region_test.c  | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c b/tools/testing/selftests/kvm/set_memory_region_test.c
index 260e638826dc..b3ece55a2da6 100644
--- a/tools/testing/selftests/kvm/set_memory_region_test.c
+++ b/tools/testing/selftests/kvm/set_memory_region_test.c
@@ -287,10 +287,15 @@ static void test_delete_memory_region(void)
 
 	vcpu_regs_get(vm, VCPU_ID, &regs);
 
-	TEST_ASSERT(regs.rip >= final_rip_start &&
-		    regs.rip < final_rip_end,
-		    "Bad rip, expected 0x%lx - 0x%lx, got 0x%llx\n",
-		    final_rip_start, final_rip_end, regs.rip);
+	/*
+	 * On AMD, after KVM_EXIT_SHUTDOWN the VMCB has been reinitialized already,
+	 * so the instruction pointer would point to the reset vector.
+	 */
+	if (run->exit_reason == KVM_EXIT_INTERNAL_ERROR)
+		TEST_ASSERT(regs.rip >= final_rip_start &&
+			    regs.rip < final_rip_end,
+			    "Bad rip, expected 0x%lx - 0x%lx, got 0x%llx\n",
+			    final_rip_start, final_rip_end, regs.rip);
 
 	kvm_vm_free(vm);
 }
-- 
2.18.2