On Wed, Jan 22, 2014 at 02:56:37PM +0000, Marc Zyngier wrote:
> In order for the guest with caches off to observe data written
nit: s/the guest/a guest/
nit: s/caches off/caches disabled/
> 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
nit: s/it/the guest/
> decides to enable it).
>
> For this purpose, hook into the coherent_cache_guest_page
> function and flush the region if the guest SCTLR
> register doesn't show the MMU and caches as being enabled.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
> arch/arm/include/asm/kvm_mmu.h | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> index cbab9ba..fa023e2 100644
> --- a/arch/arm/include/asm/kvm_mmu.h
> +++ b/arch/arm/include/asm/kvm_mmu.h
> @@ -116,9 +116,14 @@ static inline void kvm_set_s2pmd_writable(pmd_t *pmd)
>
> struct kvm;
>
> +#define kvm_flush_dcache_to_poc(a,l) __cpuc_flush_dcache_area((a), (l))
> +
> static inline void coherent_cache_guest_page(struct kvm_vcpu *vcpu, hva_t hva,
> unsigned long size)
> {
> + if ((vcpu->arch.cp15[c1_SCTLR] & 0b101) != 0b101)
> + kvm_flush_dcache_to_poc((void *)hva, size);
> +
Ah, my favorite inline function again...
> /*
> * If we are going to insert an instruction page and the icache is
> * either VIPT or PIPT, there is a potential problem where the host
> @@ -139,8 +144,6 @@ static inline void coherent_cache_guest_page(struct kvm_vcpu *vcpu, hva_t hva,
> }
> }
>
> -#define kvm_flush_dcache_to_poc(a,l) __cpuc_flush_dcache_area((a), (l))
> -
> void stage2_flush_vm(struct kvm *kvm);
>
> #endif /* !__ASSEMBLY__ */
> --
> 1.8.3.4
>
Besides the nits:
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
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