From 2d58b733c87689d3d5144e4ac94ea861cc729145 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 14 Jan 2014 19:13:10 +0000 Subject: [PATCH] arm64: KVM: force cache clean on page fault when caches are off In order for the guest with caches off to observe data written contained in a given page, we need to make sure that page is committed to memory, and not just hanging in the cache (as guest accesses are completely bypassing the cache until it decides to enable it). For this purpose, hook into the coherent_icache_guest_page function and flush the region if the guest SCTLR_EL1 register doesn't show the MMU and caches as being enabled. The function also get renamed to coherent_cache_guest_page. Signed-off-by: Marc Zyngier Reviewed-by: Catalin Marinas Reviewed-by: Christoffer Dall --- arch/arm/include/asm/kvm_mmu.h | 4 ++-- arch/arm/kvm/mmu.c | 4 ++-- arch/arm64/include/asm/kvm_mmu.h | 16 ++++++++++++---- 3 files changed, 16 insertions(+), 8 deletions(-) diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index 2d122ad..6d0f3d3 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -116,8 +116,8 @@ static inline void kvm_set_s2pmd_writable(pmd_t *pmd) struct kvm; -static inline void coherent_icache_guest_page(struct kvm *kvm, hva_t hva, - unsigned long size) +static inline void coherent_cache_guest_page(struct kvm_vcpu *vcpu, hva_t hva, + unsigned long size) { /* * If we are going to insert an instruction page and the icache is diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 7789857..fc71a8d 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -715,7 +715,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, kvm_set_s2pmd_writable(&new_pmd); kvm_set_pfn_dirty(pfn); } - coherent_icache_guest_page(kvm, hva & PMD_MASK, PMD_SIZE); + coherent_cache_guest_page(vcpu, hva & PMD_MASK, PMD_SIZE); ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd); } else { pte_t new_pte = pfn_pte(pfn, PAGE_S2); @@ -723,7 +723,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, kvm_set_s2pte_writable(&new_pte); kvm_set_pfn_dirty(pfn); } - coherent_icache_guest_page(kvm, hva, PAGE_SIZE); + coherent_cache_guest_page(vcpu, hva, PAGE_SIZE); ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false); } diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 7f1f940..6eaf69b 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -106,7 +106,6 @@ static inline bool kvm_is_write_fault(unsigned long esr) return true; } -static inline void kvm_clean_dcache_area(void *addr, size_t size) {} static inline void kvm_clean_pgd(pgd_t *pgd) {} static inline void kvm_clean_pmd_entry(pmd_t *pmd) {} static inline void kvm_clean_pte(pte_t *pte) {} @@ -124,9 +123,19 @@ static inline void kvm_set_s2pmd_writable(pmd_t *pmd) struct kvm; -static inline void coherent_icache_guest_page(struct kvm *kvm, hva_t hva, - unsigned long size) +#define kvm_flush_dcache_to_poc(a,l) __flush_dcache_area((a), (l)) + +static inline bool vcpu_has_cache_enabled(struct kvm_vcpu *vcpu) { + return (vcpu_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101; +} + +static inline void coherent_cache_guest_page(struct kvm_vcpu *vcpu, hva_t hva, + unsigned long size) +{ + if (!vcpu_has_cache_enabled(vcpu)) + kvm_flush_dcache_to_poc((void *)hva, size); + if (!icache_is_aliasing()) { /* PIPT */ flush_icache_range(hva, hva + size); } else if (!icache_is_aivivt()) { /* non ASID-tagged VIVT */ @@ -135,7 +144,6 @@ static inline void coherent_icache_guest_page(struct kvm *kvm, hva_t hva, } } -#define kvm_flush_dcache_to_poc(a,l) __flush_dcache_area((a), (l)) #define kvm_virt_to_phys(x) __virt_to_phys((unsigned long)(x)) #endif /* __ASSEMBLY__ */ -- 2.7.4