From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753568Ab2KSX57 (ORCPT ); Mon, 19 Nov 2012 18:57:59 -0500 Received: from e23smtp01.au.ibm.com ([202.81.31.143]:47771 "EHLO e23smtp01.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753204Ab2KSX56 (ORCPT ); Mon, 19 Nov 2012 18:57:58 -0500 Message-ID: <50AAC77C.8040505@linux.vnet.ibm.com> Date: Tue, 20 Nov 2012 07:57:48 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120911 Thunderbird/15.0.1 MIME-Version: 1.0 To: Avi Kivity CC: Marcelo Tosatti , LKML , KVM Subject: [PATCH 0/3] KVM: x86: improve reexecute_instruction Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit x-cbid: 12111923-1618-0000-0000-000002E2853A X-IBM-ISS-SpamDetectors: X-IBM-ISS-DetailInfo: BY=3.00000295; HX=3.00000198; KW=3.00000007; PH=3.00000001; SC=3.00000008; SDB=6.00192796; UDB=6.00043684; UTC=2012-11-19 23:54:41 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current reexecute_instruction can not well detect the failed instruction emulation. It allows guest to retry all the instructions except it accesses on error pfn. For example, these cases can not be detected: - for tdp used currently, it refused to retry all instructions. If nested npt is used, the emulation may be caused by shadow page, it can be fixed by unshadow the shadow page. - for shadow mmu some cases are nested-write-protect, for example, if the page we want to write is used as PDE but it chains to itself. Under this case, we should stop the emulation and report the case to userspace. This test case based on kvm-unit-test can trigger a infinite loop on current code (ept = 0), after this patchset, it can report the error to Qemu. Marcelo, I am afraid this test case can not be putted on kvm-unit-test, autotest is confused about this case since it can abort Qemu. Subject: [PATCH] access test: test unhandleable instruction Test the instruction which can not be handled by kvm Signed-off-by: Xiao Guangrong --- x86/access.c | 27 ++++++++++++++++++++++++++- 1 files changed, 26 insertions(+), 1 deletions(-) diff --git a/x86/access.c b/x86/access.c index 23a5995..e88db6b 100644 --- a/x86/access.c +++ b/x86/access.c @@ -2,6 +2,7 @@ #include "libcflat.h" #include "desc.h" #include "processor.h" +#include "vm.h" #define smp_id() 0 @@ -739,6 +740,28 @@ err: return 0; } +static int check_retry_unhandleable_ins(ac_pool_t *pool) +{ + unsigned long mem = 30 * 1024 * 1024; + unsigned long esp; + ac_test_t at; + + ac_test_init(&at, (void *)(0x123406003000)); + at.flags[AC_PDE_PRESENT] = at.flags[AC_PDE_WRITABLE] = 1; + at.flags[AC_PTE_PRESENT] = at.flags[AC_PTE_WRITABLE] = 1; + at.flags[AC_CPU_CR0_WP] = 1; + + at.phys = mem; + ac_setup_specific_pages(&at, pool, mem, 0); + + asm volatile("mov %%rsp, %%rax \n\t" : "=a"(esp)); + asm volatile("mov %%rax, %%rsp \n\t" : : "a"(0x123406003000 + 0xf0)); + asm volatile ("int $0x3 \n\t"); + asm volatile("mov %%rax, %%rsp \n\t" : : "a"(esp)); + + return 1; +} + int ac_test_exec(ac_test_t *at, ac_pool_t *pool) { int r; @@ -756,7 +779,8 @@ const ac_test_fn ac_test_cases[] = { corrupt_hugepage_triger, check_pfec_on_prefetch_pte, - check_smep_andnot_wp + check_smep_andnot_wp, + check_retry_unhandleable_ins }; int ac_test_run(void) @@ -770,6 +794,7 @@ int ac_test_run(void) tests = successes = 0; ac_env_int(&pool); ac_test_init(&at, (void *)(0x123400000000 + 16 * smp_id())); + do { if (at.flags[AC_CPU_CR4_SMEP] && (ptl2[2] & 0x4)) ptl2[2] -= 0x4; -- 1.7.7.6