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| author | Marc Zyngier <marc.zyngier@arm.com> | 2017-10-23 18:11:21 +0200 |
|---|---|---|
| committer | Christoffer Dall <christoffer.dall@linaro.org> | 2018-01-08 15:20:46 +0100 |
| commit | 7a3796d2ef5bb948f709467eef1bf96edbfc67a0 (patch) | |
| tree | 8b33f893ac17f71126f7960a7909d18be397353d /arch/arm | |
| parent | KVM: arm/arm64: Only clean the dcache on translation fault (diff) | |
| download | linux-7a3796d2ef5bb948f709467eef1bf96edbfc67a0.tar.xz linux-7a3796d2ef5bb948f709467eef1bf96edbfc67a0.zip | |
KVM: arm/arm64: Preserve Exec permission across R/W permission faults
So far, we loose the Exec property whenever we take permission
faults, as we always reconstruct the PTE/PMD from scratch. This
can be counter productive as we can end-up with the following
fault sequence:
X -> RO -> ROX -> RW -> RWX
Instead, we can lookup the existing PTE/PMD and clear the XN bit in the
new entry if it was already cleared in the old one, leadig to a much
nicer fault sequence:
X -> ROX -> RWX
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/kvm_mmu.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index 4d7a54cbb3ab..aab64fe52146 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -107,6 +107,11 @@ static inline bool kvm_s2pte_readonly(pte_t *pte) return (pte_val(*pte) & L_PTE_S2_RDWR) == L_PTE_S2_RDONLY; } +static inline bool kvm_s2pte_exec(pte_t *pte) +{ + return !(pte_val(*pte) & L_PTE_XN); +} + static inline void kvm_set_s2pmd_readonly(pmd_t *pmd) { pmd_val(*pmd) = (pmd_val(*pmd) & ~L_PMD_S2_RDWR) | L_PMD_S2_RDONLY; @@ -117,6 +122,11 @@ static inline bool kvm_s2pmd_readonly(pmd_t *pmd) return (pmd_val(*pmd) & L_PMD_S2_RDWR) == L_PMD_S2_RDONLY; } +static inline bool kvm_s2pmd_exec(pmd_t *pmd) +{ + return !(pmd_val(*pmd) & PMD_SECT_XN); +} + static inline bool kvm_page_empty(void *ptr) { struct page *ptr_page = virt_to_page(ptr); |