Hi Eric,
On 03/04/14 16:17, Eric Auger wrote:
> Currently when a KVM region is removed using
> kvm_vm_ioctl_set_memory_region (with memory region size equal to 0), the
> corresponding intermediate physical memory is not unmapped.
>
> This patch unmaps the region's IPA range in
> kvm_arch_commit_memory_region using unmap_stage2_range.
>
> The patch was tested on QEMU VFIO based use case where RAM memory region
> creation/deletion frequently happens for IRQ handling.
>
> Notes:
> - the KVM_MR_MOVE case shall request some similar addition but I cannot test
> this currently
I think you should try to handle it anyway. I'm sure you could hack QEMU
to do this test it, but even if you don't, better plug that hole right now.
> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
> ---
> arch/arm/include/asm/kvm_mmu.h | 2 ++
> arch/arm/kvm/arm.c | 8 ++++++++
> arch/arm/kvm/mmu.c | 2 +-
> 3 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> index 2d122ad..a91c863 100644
> --- a/arch/arm/include/asm/kvm_mmu.h
> +++ b/arch/arm/include/asm/kvm_mmu.h
> @@ -52,6 +52,8 @@ 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);
>
> +void unmap_stage2_range(struct kvm *kvm, phys_addr_t guest_ipa, u64 size);
> +
> int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run);
>
> void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index bd18bb8..9a4bc10 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -241,6 +241,14 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
> const struct kvm_memory_slot *old,
> enum kvm_mr_change change)
> {
> + if (change == KVM_MR_DELETE) {
> + gpa_t gpa = old->base_gfn << PAGE_SHIFT;
> + u64 size = old->npages << PAGE_SHIFT;
> +
> + spin_lock(&kvm->mmu_lock);
> + unmap_stage2_range(kvm, gpa, size);
> + spin_unlock(&kvm->mmu_lock);
> + }
> }
Just move the whole function to mmu.c, as it makes more sense to have it
there. And while you're at it, how about moving the other
memslot/memory_region stubs?
> void kvm_arch_flush_shadow_all(struct kvm *kvm)
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index 7789857..e8580e2 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -443,7 +443,7 @@ int kvm_alloc_stage2_pgd(struct kvm *kvm)
> * destroying the VM), otherwise another faulting VCPU may come in and mess
> * with things behind our backs.
> */
> -static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size)
> +void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size)
> {
> unmap_range(kvm, kvm->arch.pgd, start, size);
> }
>
Looks sensible otherwise.
Thanks!
M.
--
Jazz is not dead. It just smells funny...
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