On Wed, Sep 17, 2014 at 02:56:18PM -0700, Ard Biesheuvel wrote:
> Add support for read-only MMIO passthrough mappings by adding a
> 'writable' parameter to kvm_phys_addr_ioremap. For the moment,
> mappings will be read-write even if 'writable' is false, but once
> the definition of PAGE_S2_DEVICE gets changed, those mappings will
> be created read-only.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> ---
> arch/arm/kvm/mmu.c | 5 ++++-
> arch/arm64/include/asm/kvm_mmu.h | 2 +-
> virt/kvm/arm/vgic.c | 3 ++-
> 3 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index c093e95ff7ef..fe53c3a30383 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -674,7 +674,7 @@ static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
> * @size: The size of the mapping
> */
> int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
> - phys_addr_t pa, unsigned long size)
> + phys_addr_t pa, unsigned long size, bool writable)
> {
> phys_addr_t addr, end;
> int ret = 0;
> @@ -687,6 +687,9 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
> for (addr = guest_ipa; addr < end; addr += PAGE_SIZE) {
> pte_t pte = pfn_pte(pfn, PAGE_S2_DEVICE);
>
> + if (writable)
> + kvm_set_s2pte_writable(&pte);
> +
> ret = mmu_topup_memory_cache(&cache, 2, 2);
> if (ret)
> goto out;
> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
> index 737da742b293..7474e611bb2a 100644
> --- a/arch/arm64/include/asm/kvm_mmu.h
> +++ b/arch/arm64/include/asm/kvm_mmu.h
> @@ -78,7 +78,7 @@ void free_hyp_pgds(void);
> int kvm_alloc_stage2_pgd(struct kvm *kvm);
> void kvm_free_stage2_pgd(struct kvm *kvm);
> int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
> - phys_addr_t pa, unsigned long size);
> + phys_addr_t pa, unsigned long size, bool writable);
>
> int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run);
>
> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> index 73eba793b17f..c2bdbf4e25c2 100644
> --- a/virt/kvm/arm/vgic.c
> +++ b/virt/kvm/arm/vgic.c
> @@ -1628,7 +1628,8 @@ int kvm_vgic_init(struct kvm *kvm)
> }
>
> ret = kvm_phys_addr_ioremap(kvm, kvm->arch.vgic.vgic_cpu_base,
> - vgic->vcpu_base, KVM_VGIC_V2_CPU_SIZE);
> + vgic->vcpu_base, KVM_VGIC_V2_CPU_SIZE,
> + true);
> if (ret) {
> kvm_err("Unable to remap VGIC CPU to VCPU\n");
> goto out;
> --
> 1.8.3.2
>
You forgot the 32-bit prototype, but I can fix that up when applying it.
Thanks,
-Christoffer
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