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* [PATCH kvm-unit-tests] access: check SMEP on prefetch pte path
@ 2011-06-24  7:16 Yang, Wei
  2011-06-24  9:11 ` Xiao Guangrong
  0 siblings, 1 reply; 4+ messages in thread
From: Yang, Wei @ 2011-06-24  7:16 UTC (permalink / raw)
  To: avi; +Cc: kvm, xin.li, haitao.shan, Yang, Wei

This patch checks SMEP on prefetch pte path when
cr0.wp=1 and cr0.wp=0.

 Signed-off-by: Yang, Wei <wei.y.yang@intel.com>
 Signed-off-by: Li, Xin <xin.li@intel.com>
 Signed-off-by: Shan, Haitao <haitao.shan@intel.com>

---
 x86/access.c   |   92 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 x86/cstart64.S |    1 +
 2 files changed, 90 insertions(+), 3 deletions(-)

diff --git a/x86/access.c b/x86/access.c
index 7c8b9a5..71f04e0 100644
--- a/x86/access.c
+++ b/x86/access.c
@@ -27,6 +27,7 @@ typedef unsigned long pt_element_t;
 #define PT_NX_MASK         ((pt_element_t)1 << 63)
 
 #define CR0_WP_MASK (1UL << 16)
+#define CR4_SMEP_MASK (1UL << 20)
 
 #define PFERR_PRESENT_MASK (1U << 0)
 #define PFERR_WRITE_MASK (1U << 1)
@@ -70,6 +71,7 @@ enum {
 
     AC_CPU_EFER_NX,
     AC_CPU_CR0_WP,
+    AC_CPU_CR4_SMEP,
 
     NR_AC_FLAGS
 };
@@ -140,6 +142,16 @@ void set_cr0_wp(int wp)
     write_cr0(cr0);
 }
 
+void set_cr4_smep(int smep)
+{
+    unsigned long cr4 = read_cr4();
+
+    cr4 &= ~CR4_SMEP_MASK;
+    if (smep)
+	cr4 |= CR4_SMEP_MASK;
+    write_cr4(cr4);
+}
+
 void set_efer_nx(int nx)
 {
     unsigned long long efer;
@@ -176,7 +188,7 @@ void ac_test_init(ac_test_t *at, void *virt)
 
 int ac_test_bump_one(ac_test_t *at)
 {
-    for (int i = 0; i < NR_AC_FLAGS; ++i)
+    for (int i = 0; i < NR_AC_FLAGS-1; ++i)
 	if (!at->flags[i]) {
 	    at->flags[i] = 1;
 	    return 1;
@@ -287,6 +299,9 @@ void ac_set_expected_status(ac_test_t *at)
     if (at->flags[AC_PDE_PSE]) {
 	if (at->flags[AC_ACCESS_WRITE] && !at->expected_fault)
 	    at->expected_pde |= PT_DIRTY_MASK;
+	if (at->flags[AC_ACCESS_FETCH] && at->flags[AC_PDE_USER]
+	    && at->flags[AC_CPU_CR4_SMEP])
+	    at->expected_fault = 1;
 	goto no_pte;
     }
 
@@ -306,7 +321,11 @@ void ac_set_expected_status(ac_test_t *at)
 	&& (at->flags[AC_CPU_CR0_WP] || at->flags[AC_ACCESS_USER]))
 	at->expected_fault = 1;
 
-    if (at->flags[AC_ACCESS_FETCH] && at->flags[AC_PTE_NX])
+    if (at->flags[AC_ACCESS_FETCH]
+	&& (at->flags[AC_PTE_NX]
+	    || (at->flags[AC_CPU_CR4_SMEP]
+		&& at->flags[AC_PDE_USER]
+		&& at->flags[AC_PTE_USER])))
 	at->expected_fault = 1;
 
     if (at->expected_fault)
@@ -320,7 +339,7 @@ no_pte:
 fault:
     if (!at->expected_fault)
         at->ignore_pde = 0;
-    if (!at->flags[AC_CPU_EFER_NX])
+    if (!at->flags[AC_CPU_EFER_NX] && !at->flags[AC_CPU_CR4_SMEP])
         at->expected_error &= ~PFERR_FETCH_MASK;
 }
 
@@ -645,6 +664,72 @@ err:
     return 0;
 }
 
+static int check_smep_on_prefetch_pte(ac_pool_t *pool)
+{
+	ac_test_t at1;
+	int err_smep, err_prepare_notwp, err_smep_notwp;
+	extern u64 ptl2[];
+
+	ac_test_init(&at1, (void *)(0x123406001000));
+
+	at1.flags[AC_PDE_PRESENT] = 1;
+	at1.flags[AC_PTE_PRESENT] = 1;
+	at1.flags[AC_PDE_USER] = 1;
+	at1.flags[AC_PTE_USER] = 1;
+	at1.flags[AC_PDE_ACCESSED] = 1;
+	at1.flags[AC_PTE_ACCESSED] = 1;
+	at1.flags[AC_ACCESS_FETCH] = 1;
+	at1.flags[AC_CPU_CR4_SMEP] = 1;
+	at1.flags[AC_CPU_CR0_WP] = 1;
+	ac_test_setup_pte(&at1, pool);
+	ptl2[2] -= 0x4;
+	set_cr4_smep(at1.flags[AC_CPU_CR4_SMEP]);
+	err_smep = ac_test_do_access(&at1);
+	if (!err_smep) {
+		printf("%s: check SMEP on prefetch pte path with wp"
+		       "fail\n", __FUNCTION__);
+		goto clean_up;
+	}
+
+	/*
+	 * Here we write the ro user page when
+	 * cr0.wp=0, then we execute it and SMEP
+	 * fault should happen.
+	 */
+	at1.flags[AC_ACCESS_WRITE] = 1;
+	at1.flags[AC_ACCESS_FETCH] = 0;
+	at1.flags[AC_CPU_CR0_WP] = 0;
+	ac_set_expected_status(&at1);
+	err_prepare_notwp = ac_test_do_access(&at1);
+	if (!err_prepare_notwp) {
+		printf("%s: SMEP prepare fail\n", __FUNCTION__);
+		goto clean_up;
+	}
+
+	at1.flags[AC_ACCESS_WRITE] = 0;
+	at1.flags[AC_ACCESS_FETCH] = 1;
+	ac_set_expected_status(&at1);
+	err_smep_notwp = ac_test_do_access(&at1);
+
+clean_up:
+	at1.flags[AC_CPU_CR4_SMEP] = 0;
+	set_cr4_smep(at1.flags[AC_CPU_CR4_SMEP]);
+	ptl2[2] += 0x4;
+
+	if (!err_smep || !err_prepare_notwp)
+		goto err;
+	if (!err_smep_notwp) {
+		printf("%s: check SMEP on prefetch pte path without wp"
+		       "fail\n", __FUNCTION__);
+			__FUNCTION__);
+		goto err;
+	}
+	return 1;
+
+err:
+	return 0;
+}
+
 int ac_test_exec(ac_test_t *at, ac_pool_t *pool)
 {
     int r;
@@ -662,6 +747,7 @@ const ac_test_fn ac_test_cases[] =
 {
 	corrupt_hugepage_triger,
 	check_pfec_on_prefetch_pte,
+	check_smep_on_prefetch_pte
 };
 
 int ac_test_run(void)
diff --git a/x86/cstart64.S b/x86/cstart64.S
index 71014d8..24df5f8 100644
--- a/x86/cstart64.S
+++ b/x86/cstart64.S
@@ -21,6 +21,7 @@ ring0stacktop:
 .data
 
 .align 4096
+.globl ptl2
 ptl2:
 i = 0
 	.rept 512 * 4
-- 
1.7.4.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-06-27  6:00 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-06-24  7:16 [PATCH kvm-unit-tests] access: check SMEP on prefetch pte path Yang, Wei
2011-06-24  9:11 ` Xiao Guangrong
2011-06-25  2:44   ` Yang, Wei Y
2011-06-27  6:02     ` Xiao Guangrong

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