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From: Gavin Shan <gshan@redhat.com>
To: Keqian Zhu <zhukeqian1@huawei.com>, kvmarm@lists.cs.columbia.edu
Cc: maz@kernel.org, will@kernel.org, linux-kernel@vger.kernel.org,
	shan.gavin@gmail.com
Subject: Re: [PATCH 3/4] KVM: arm64: Fix address check for memory slot
Date: Mon, 15 Mar 2021 20:46:30 +1100	[thread overview]
Message-ID: <b7aaa914-04f7-4560-4a53-393adaccd27d@redhat.com> (raw)
In-Reply-To: <be57b9fb-89c4-9c32-f273-9f4bbe973b00@huawei.com>

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 <gshan@redhat.com>
>> ---
>>   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;
>>   
>>
> 


  reply	other threads:[~2021-03-15  9:47 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-15  4:18 [PATCH 0/4] KVM: arm64: Minor page fault handler improvement Gavin Shan
2021-03-15  4:18 ` [PATCH 1/4] KVM: arm64: Hide kvm_mmu_wp_memory_region() Gavin Shan
2021-03-15  7:49   ` Keqian Zhu
2021-03-15  4:18 ` [PATCH 2/4] KVM: arm64: Use find_vma_intersection() Gavin Shan
2021-03-15  8:04   ` Keqian Zhu
2021-03-15  9:42     ` Gavin Shan
2021-03-16  3:52       ` Gavin Shan
2021-03-16  4:20         ` Keqian Zhu
2021-03-15  8:52   ` Marc Zyngier
2021-03-15  9:40     ` Gavin Shan
2021-03-15  4:18 ` [PATCH 3/4] KVM: arm64: Fix address check for memory slot Gavin Shan
2021-03-15  7:33   ` Keqian Zhu
2021-03-15  9:46     ` Gavin Shan [this message]
2021-03-15  4:18 ` [PATCH 4/4] KVM: arm64: Don't retrieve memory slot again in page fault handler Gavin Shan
2021-03-15  8:25   ` Keqian Zhu
2021-03-15  9:56     ` Gavin Shan
2021-03-15 10:46       ` Keqian Zhu

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