The series includes several minior improvements to stage-2 page fault
handler: PATCH[1/2] are cleaning up the code. PATCH[3] fixes the address
range check on adding new memory slot. PATCH[4] don't retrieve the memory
slot again in the page fault handler to save a bit CPU cycles.
Gavin Shan (4):
KVM: arm64: Hide kvm_mmu_wp_memory_region()
KVM: arm64: Use find_vma_intersection()
KVM: arm64: Fix address check for memory slot
KVM: arm64: Don't retrieve memory slot again in page fault handler
arch/arm64/include/asm/kvm_host.h | 1 -
arch/arm64/kvm/mmu.c | 19 +++++++++++--------
2 files changed, 11 insertions(+), 9 deletions(-)
--
2.23.0
The last (IPA) page can't be specified when a new memory slot is
added. The error -EFAULT is returned when the memory slot is added
with the following parameters for the VM, which has 40-bits IPA
limit. The host has 4KB base page size. It's not correct because
the last (IPA) page is still usable.
struct kvm_userspace_memory_region {
__u32 slot; /* 1 */
__u32 flags; /* 0 */
__u64 guest_phys_addr; /* 0xfffffff000 */
__u64 memory_size; /* 0x1000 */
__u64 userspace_addr;
};
Signed-off-by: Gavin Shan <[email protected]>
---
arch/arm64/kvm/mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 286b603ed0d3..a5a8ade9fde4 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1313,7 +1313,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
* Prevent userspace from creating a memory region outside of the IPA
* space addressable by the KVM guest IPA space.
*/
- if (memslot->base_gfn + memslot->npages >=
+ if (memslot->base_gfn + memslot->npages >
(kvm_phys_size(kvm) >> PAGE_SHIFT))
return -EFAULT;
--
2.23.0
Hi Gavin,
FYI, this has been fixed by Marc in commit 262b003d059c.
Thanks,
Keqian
On 2021/3/15 12:18, Gavin Shan wrote:
> The last (IPA) page can't be specified when a new memory slot is
> added. The error -EFAULT is returned when the memory slot is added
> with the following parameters for the VM, which has 40-bits IPA
> limit. The host has 4KB base page size. It's not correct because
> the last (IPA) page is still usable.
>
> struct kvm_userspace_memory_region {
> __u32 slot; /* 1 */
> __u32 flags; /* 0 */
> __u64 guest_phys_addr; /* 0xfffffff000 */
> __u64 memory_size; /* 0x1000 */
> __u64 userspace_addr;
> };
>
> Signed-off-by: Gavin Shan <[email protected]>
> ---
> arch/arm64/kvm/mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 286b603ed0d3..a5a8ade9fde4 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -1313,7 +1313,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
> * Prevent userspace from creating a memory region outside of the IPA
> * space addressable by the KVM guest IPA space.
> */
> - if (memslot->base_gfn + memslot->npages >=
> + if (memslot->base_gfn + memslot->npages >
> (kvm_phys_size(kvm) >> PAGE_SHIFT))
> return -EFAULT;
>
>
Hi Keqian,
On 3/15/21 6:33 PM, Keqian Zhu wrote:
> FYI, this has been fixed by Marc in commit 262b003d059c.
>
Yeah, I didn't check 5.12.rc3 code where the issue has been
fixed. So please ignore this one and sorry for the noise.
Thanks,
Gavin
> On 2021/3/15 12:18, Gavin Shan wrote:
>> The last (IPA) page can't be specified when a new memory slot is
>> added. The error -EFAULT is returned when the memory slot is added
>> with the following parameters for the VM, which has 40-bits IPA
>> limit. The host has 4KB base page size. It's not correct because
>> the last (IPA) page is still usable.
>>
>> struct kvm_userspace_memory_region {
>> __u32 slot; /* 1 */
>> __u32 flags; /* 0 */
>> __u64 guest_phys_addr; /* 0xfffffff000 */
>> __u64 memory_size; /* 0x1000 */
>> __u64 userspace_addr;
>> };
>>
>> Signed-off-by: Gavin Shan <[email protected]>
>> ---
>> arch/arm64/kvm/mmu.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
>> index 286b603ed0d3..a5a8ade9fde4 100644
>> --- a/arch/arm64/kvm/mmu.c
>> +++ b/arch/arm64/kvm/mmu.c
>> @@ -1313,7 +1313,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
>> * Prevent userspace from creating a memory region outside of the IPA
>> * space addressable by the KVM guest IPA space.
>> */
>> - if (memslot->base_gfn + memslot->npages >=
>> + if (memslot->base_gfn + memslot->npages >
>> (kvm_phys_size(kvm) >> PAGE_SHIFT))
>> return -EFAULT;
>>
>>
>