From: Paolo Bonzini <pbonzini@redhat.com>
To: Xiao Guangrong <guangrong.xiao@linux.intel.com>,
Neo Jia <cjia@nvidia.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
"Kirti Wankhede" <kwankhede@nvidia.com>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Subject: Re: [PATCH 0/2] KVM: MMU: support VMAs that got remap_pfn_range-ed
Date: Mon, 4 Jul 2016 09:48:52 +0200 [thread overview]
Message-ID: <8ff54c7b-2e64-4503-03f6-1a858d9d5746@redhat.com> (raw)
In-Reply-To: <577A123F.1060909@linux.intel.com>
On 04/07/2016 09:37, Xiao Guangrong wrote:
>>>
>>
>> It actually is a portion of the physical mmio which is set by vfio mmap.
>
> So i do not think we need to care its refcount, i,e, we can consider it
> as reserved_pfn,
> Paolo?
nVidia provided me (offlist) with a simple patch that modified VFIO to
exhibit the problem, and it didn't use reserved PFNs. This is why the
commit message for the patch is not entirely accurate.
But apart from this, it's much more obvious to consider the refcount.
The x86 MMU code doesn't care if the page is reserved or not;
mmu_set_spte does a kvm_release_pfn_clean, hence it makes sense for
hva_to_pfn_remapped to try doing a get_page (via kvm_get_pfn) after
invoking the fault handler, just like the get_user_pages family of
function does.
Paolo
next prev parent reply other threads:[~2016-07-04 7:49 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-30 13:01 [PATCH 0/2] KVM: MMU: support VMAs that got remap_pfn_range-ed Paolo Bonzini
2016-06-30 13:01 ` [PATCH 1/2] KVM: MMU: prepare to support mapping of VM_IO and VM_PFNMAP frames Paolo Bonzini
2016-06-30 13:01 ` [PATCH 2/2] KVM: MMU: try to fix up page faults before giving up Paolo Bonzini
2016-06-30 21:59 ` [PATCH 0/2] KVM: MMU: support VMAs that got remap_pfn_range-ed Neo Jia
2016-07-04 6:39 ` Xiao Guangrong
2016-07-04 7:03 ` Neo Jia
2016-07-04 7:37 ` Xiao Guangrong
2016-07-04 7:48 ` Paolo Bonzini [this message]
2016-07-04 7:59 ` Xiao Guangrong
2016-07-04 8:14 ` Paolo Bonzini
2016-07-04 8:21 ` Xiao Guangrong
2016-07-04 8:48 ` Paolo Bonzini
2016-07-04 7:53 ` Neo Jia
2016-07-04 8:19 ` Xiao Guangrong
2016-07-04 8:41 ` Neo Jia
2016-07-04 8:45 ` Xiao Guangrong
2016-07-04 8:54 ` Xiao Guangrong
2016-07-04 9:16 ` Neo Jia
2016-07-04 10:16 ` Xiao Guangrong
2016-07-04 15:33 ` Neo Jia
2016-07-05 1:19 ` Xiao Guangrong
2016-07-05 1:35 ` Neo Jia
2016-07-05 4:02 ` Xiao Guangrong
2016-07-05 5:16 ` Neo Jia
2016-07-05 6:26 ` Xiao Guangrong
2016-07-05 7:30 ` Neo Jia
2016-07-05 9:02 ` Xiao Guangrong
2016-07-05 15:07 ` Neo Jia
2016-07-06 2:22 ` Xiao Guangrong
2016-07-06 4:01 ` Neo Jia
2016-07-04 7:38 ` Paolo Bonzini
2016-07-04 7:40 ` Xiao Guangrong
2016-07-05 5:41 ` Neo Jia
2016-07-05 12:18 ` Paolo Bonzini
2016-07-05 14:02 ` Neo Jia
2016-07-06 2:00 ` Xiao Guangrong
2016-07-06 2:18 ` Neo Jia
2016-07-06 2:35 ` Xiao Guangrong
2016-07-06 2:57 ` Neo Jia
2016-07-06 4:02 ` Xiao Guangrong
2016-07-06 11:48 ` Paolo Bonzini
2016-07-07 2:36 ` Xiao Guangrong
2016-07-06 6:05 ` Paolo Bonzini
2016-07-06 15:50 ` Alex Williamson
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