[PATCH 1/2] KVM: test: add the test case to check PFEC on prefetch pte path

[PATCH 1/2] KVM: test: add the test case to check PFEC on prefetch pte path

[Xiao Guangrong]

Check page fault error code on prefetch pte path

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 x86/access.c |   74 +++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 files changed, 66 insertions(+), 8 deletions(-)

diff --git a/x86/access.c b/x86/access.c
index 067565b..f43f7f1 100644
--- a/x86/access.c
+++ b/x86/access.c
@@ -408,7 +408,9 @@ fault:
         at->expected_error &= ~PFERR_FETCH_MASK;
 }
 
-void ac_test_setup_pte(ac_test_t *at, ac_pool_t *pool)
+void __ac_setup_specific_pages(ac_test_t *at, ac_pool_t *pool, u64 pd_page,
+			       u64 pt_page)
+
 {
     unsigned long root = read_cr3();
 
@@ -423,13 +425,12 @@ void ac_test_setup_pte(ac_test_t *at, ac_pool_t *pool)
 	switch (i) {
 	case 4:
 	case 3:
-	    pte = vroot[index];
-	    pte = ac_test_alloc_pt(pool) | PT_PRESENT_MASK;
-	    pte |= PT_WRITABLE_MASK | PT_USER_MASK;
+	    pte = pd_page ? pd_page : ac_test_alloc_pt(pool);
+	    pte |= PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK;
 	    break;
 	case 2:
 	    if (!at->flags[AC_PDE_PSE])
-		pte = ac_test_alloc_pt(pool);
+		pte = pt_page ? pt_page : ac_test_alloc_pt(pool);
 	    else {
 		pte = at->phys & PT_PSE_BASE_ADDR_MASK;
 		pte |= PT_PSE_MASK;
@@ -475,6 +476,17 @@ void ac_test_setup_pte(ac_test_t *at, ac_pool_t *pool)
     ac_set_expected_status(at);
 }
 
+static void ac_test_setup_pte(ac_test_t *at, ac_pool_t *pool)
+{
+	__ac_setup_specific_pages(at, pool, 0, 0);
+}
+
+static void ac_setup_specific_pages(ac_test_t *at, ac_pool_t *pool,
+				    u64 pd_page, u64 pt_page)
+{
+	return __ac_setup_specific_pages(at, pool, pd_page, pt_page);
+}
+
 static void ac_test_check(ac_test_t *at, _Bool *success_ret, _Bool cond,
                           const char *fmt, ...)
 {
@@ -663,6 +675,43 @@ err:
     return 0;
 }
 
+/*
+ * This test case is used to triger the bug which is fixed by
+ * commit 3ddf6c06e13e in the kvm tree
+ */
+static int check_pfec_on_prefetch_pte(ac_pool_t *pool)
+{
+	ac_test_t at1, at2;
+
+	ac_test_init(&at1, (void *)(0x123406001000));
+	ac_test_init(&at2, (void *)(0x123406003000));
+
+	at1.flags[AC_PDE_PRESENT] = 1;
+	at1.flags[AC_PTE_PRESENT] = 1;
+	ac_setup_specific_pages(&at1, pool, 30 * 1024 * 1024, 30 * 1024 * 1024);
+
+	at2.flags[AC_PDE_PRESENT] = 1;
+	at2.flags[AC_PTE_NX] = 1;
+	at2.flags[AC_PTE_PRESENT] = 1;
+	ac_setup_specific_pages(&at2, pool, 30 * 1024 * 1024, 30 * 1024 * 1024);
+
+	if (!ac_test_do_access(&at1)) {
+		printf("%s: prepare fail\n", __FUNCTION__);
+		goto err;
+	}
+
+	if (!ac_test_do_access(&at2)) {
+		printf("%s: check PFEC on prefetch pte path fail\n",
+			__FUNCTION__);
+		goto err;
+	}
+
+	return 1;
+
+err:
+    return 0;
+}
+
 int ac_test_exec(ac_test_t *at, ac_pool_t *pool)
 {
     int r;
@@ -675,11 +724,18 @@ int ac_test_exec(ac_test_t *at, ac_pool_t *pool)
     return r;
 }
 
+typedef int (*ac_test_fn)(ac_pool_t *pool);
+const ac_test_fn ac_test_cases[] =
+{
+	corrupt_hugepage_triger,
+	check_pfec_on_prefetch_pte,
+};
+
 int ac_test_run(void)
 {
     ac_test_t at;
     ac_pool_t pool;
-    int tests, successes;
+    int i, tests, successes;
 
     printf("run\n");
     tests = successes = 0;
@@ -690,8 +746,10 @@ int ac_test_run(void)
 	successes += ac_test_exec(&at, &pool);
     } while (ac_test_bump(&at));
 
-    ++tests;
-    successes += corrupt_hugepage_triger(&pool);
+    for (i = 0; i < ARRAY_SIZE(ac_test_cases); i++) {
+	++tests;
+	successes += ac_test_cases[i](&pool);
+    }
 
     printf("\n%d tests, %d failures\n", tests, tests - successes);
 
-- 
1.7.0.4

[PATCH 2/2] KVM: test: dump page mapping if test fail

[Xiao Guangrong]

It can help us to fix the bug

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 x86/access.c |   22 +++++++++++++++++++++-
 1 files changed, 21 insertions(+), 1 deletions(-)

diff --git a/x86/access.c b/x86/access.c
index f43f7f1..709d1a6 100644
--- a/x86/access.c
+++ b/x86/access.c
@@ -35,6 +35,9 @@ typedef unsigned long pt_element_t;
 #define MSR_EFER 0xc0000080
 #define EFER_NX_MASK		(1ull << 11)
 
+#define PT_INDEX(address, level)       \
+       ((address) >> (12 + ((level)-1) * 9)) & 511
+
 /*
  * page table access check tests
  */
@@ -420,7 +423,7 @@ void __ac_setup_specific_pages(ac_test_t *at, ac_pool_t *pool, u64 pd_page,
     at->ptep = 0;
     for (int i = 4; i >= 1 && (i >= 2 || !at->flags[AC_PDE_PSE]); --i) {
 	pt_element_t *vroot = va(root & PT_BASE_ADDR_MASK);
-	unsigned index = ((unsigned long)at->virt >> (12 + (i-1) * 9)) & 511;
+	unsigned index = PT_INDEX((unsigned long)at->virt, i);
 	pt_element_t pte = 0;
 	switch (i) {
 	case 4:
@@ -487,6 +490,22 @@ static void ac_setup_specific_pages(ac_test_t *at, ac_pool_t *pool,
 	return __ac_setup_specific_pages(at, pool, pd_page, pt_page);
 }
 
+static void dump_mapping(ac_test_t *at)
+{
+	unsigned long root = read_cr3();
+	int i;
+
+	printf("Dump mapping: address: %llx\n", at->virt);
+	for (i = 4; i >= 1 && (i >= 2 || !at->flags[AC_PDE_PSE]); --i) {
+		pt_element_t *vroot = va(root & PT_BASE_ADDR_MASK);
+		unsigned index = PT_INDEX((unsigned long)at->virt, i);
+		pt_element_t pte = vroot[index];
+
+		printf("------L%d: %llx\n", i, pte);
+		root = vroot[index];
+	}
+}
+
 static void ac_test_check(ac_test_t *at, _Bool *success_ret, _Bool cond,
                           const char *fmt, ...)
 {
@@ -511,6 +530,7 @@ static void ac_test_check(ac_test_t *at, _Bool *success_ret, _Bool cond,
     vsnprintf(buf, sizeof(buf), fmt, ap);
     va_end(ap);
     printf("FAIL: %s\n", buf);
+    dump_mapping(at);
 }
 
 static int pt_match(pt_element_t pte1, pt_element_t pte2, pt_element_t ignore)
-- 
1.7.0.4

Re: [PATCH 1/2] KVM: test: add the test case to check PFEC on prefetch pte path

[Avi Kivity]

On 12/23/2010 10:10 AM, Xiao Guangrong wrote:
> Check page fault error code on prefetch pte path

Applied both, thanks.

-- 
error compiling committee.c: too many arguments to function

Re: [PATCH 1/2] KVM: test: add the test case to check PFEC on prefetch pte path

[Avi Kivity]

On 12/23/2010 10:10 AM, Xiao Guangrong wrote:
> Check page fault error code on prefetch pte path
>

Can you point out the commit which fixed this failure?  I'd like to 
backport it if it's simple enough.

-- 
error compiling committee.c: too many arguments to function

Re: [PATCH 1/2] KVM: test: add the test case to check PFEC on prefetch pte path

[Xiao Guangrong]

On 01/03/2011 11:11 PM, Avi Kivity wrote:
> On 12/23/2010 10:10 AM, Xiao Guangrong wrote:
>> Check page fault error code on prefetch pte path
>>
> 
> Can you point out the commit which fixed this failure?  I'd like to backport it if it's simple enough.
> 

The commit is 3ddf6c06e13e:

commit 3ddf6c06e13ef7842e58815d28ec88faae19c8db
Author: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Date:   Wed Nov 17 12:11:41 2010 +0800

    KVM: MMU: don't mark spte notrap if reserved bit set
    
    If reserved bit is set, we need inject the #PF with PFEC.RSVD=1,
    but shadow_notrap_nonpresent_pte injects #PF with PFEC.RSVD=0 only
    
    Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
    Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>