On Wed, Jan 22, 2014 at 02:56:33PM +0000, Marc Zyngier wrote:
> 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 <marc.zyngier@xxxxxxx>
> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> ---
> arch/arm/include/asm/kvm_mmu.h | 4 ++--
> arch/arm/kvm/mmu.c | 4 ++--
> arch/arm64/include/asm/kvm_mmu.h | 11 +++++++----
> 3 files changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> index 77de4a4..f997b9e 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 5809069..415fd63 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -713,7 +713,7 @@ 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);
> @@ -721,7 +721,7 @@ 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 680f74e..2232dd0 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 +123,14 @@ 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 void coherent_cache_guest_page(struct kvm_vcpu *vcpu, hva_t hva,
> + unsigned long size)
> {
> + if ((vcpu_sys_reg(vcpu, SCTLR_EL1) & 0b101) != 0b101)
> + kvm_flush_dcache_to_poc((void *)hva, size);
> +
This deserves a comment or a static inline...
> if (!icache_is_aliasing()) { /* PIPT */
> flush_icache_range(hva, hva + size);
> } else if (!icache_is_aivivt()) { /* non ASID-tagged VIVT */
> @@ -135,7 +139,6 @@ 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))
>
> #endif /* __ASSEMBLY__ */
> #endif /* __ARM64_KVM_MMU_H__ */
> --
> 1.8.3.4
>
Otherwise:
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
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