On Mon, Nov 10, 2014 at 09:33:55AM +0100, Ard Biesheuvel wrote:
> Instead of using kvm_is_mmio_pfn() to decide whether a host region
> should be stage 2 mapped with device attributes, add a new static
> function kvm_is_device_pfn() that disregards RAM pages with the
> reserved bit set, as those should usually not be mapped as device
> memory.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> ---
> arch/arm/kvm/mmu.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index 57a403a5c22b..b007438242e2 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -834,6 +834,11 @@ static bool kvm_is_write_fault(struct kvm_vcpu *vcpu)
> return kvm_vcpu_dabt_iswrite(vcpu);
> }
>
> +static bool kvm_is_device_pfn(unsigned long pfn)
> +{
> + return !pfn_valid(pfn);
> +}
So this works for Magnus' use case, because a device tree memreserve
results in reserved, but valid, existing pages being backed by a struct
page?
> +
> static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> struct kvm_memory_slot *memslot, unsigned long hva,
> unsigned long fault_status)
> @@ -904,7 +909,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> if (is_error_pfn(pfn))
> return -EFAULT;
>
> - if (kvm_is_mmio_pfn(pfn))
> + if (kvm_is_device_pfn(pfn))
> mem_type = PAGE_S2_DEVICE;
>
> spin_lock(&kvm->mmu_lock);
> --
> 1.8.3.2
>
If my understanding above is correct, then:
Acked-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
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