On 06/24/2011 03:16 PM, Yang, Wei wrote:
> +void set_cr4_smep(int smep)
> +{
> + unsigned long cr4 = read_cr4();
> +
> + cr4 &= ~CR4_SMEP_MASK;
> + if (smep)
> + cr4 |= CR4_SMEP_MASK;
> + write_cr4(cr4);
> +}
> +
It can work if the box does not support SMEP?
> 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)
Why not test "SMEP" for all test case?
> 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;
> }
>
You check the AC_CPU_CR4_SMEP for all case, but only set the cr4 bit for
check_smep_on_prefetch_pte(), it is better to move set_cr4_smep to
ac_test_do_access()?
> @@ -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;
Why is it needed? :-)
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