From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v5 00/12] KVM: introduce readonly memslot
Date: Tue, 14 Aug 2012 17:00:33 +0300 [thread overview]
Message-ID: <502A5A01.6040505@redhat.com> (raw)
In-Reply-To: <20120810181422.GA14892@amt.cnet>
On 08/10/2012 09:14 PM, Marcelo Tosatti wrote:
> On Tue, Aug 07, 2012 at 05:47:15PM +0800, Xiao Guangrong wrote:
>> Changelog:
>> - introduce KVM_PFN_ERR_RO_FAULT instead of dummy page
>> - introduce KVM_HVA_ERR_BAD and optimize error hva indicators
>>
>> The test case can be found at:
>> http://lkml.indiana.edu/hypermail/linux/kernel/1207.2/00819/migrate-perf.tar.bz2
>>
>> In current code, if we map a readonly memory space from host to guest
>> and the page is not currently mapped in the host, we will get a fault-pfn
>> and async is not allowed, then the vm will crash.
>>
>> As Avi's suggestion, We introduce readonly memory region to map ROM/ROMD
>> to the guest, read access is happy for readonly memslot, write access on
>> readonly memslot will cause KVM_EXIT_MMIO exit.
>
> Memory slots whose QEMU mapping is write protected is supported
> today, as long as there are no write faults.
>
> What prevents the use of mmap(!MAP_WRITE) to handle read-only memslots
> again?
Userspace may want to modify the ROM (for example, when programming a
flash device). It is also possible to map an hva range rw through one
slot and ro through another.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-08-14 14:00 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-07 9:47 [PATCH v5 00/12] KVM: introduce readonly memslot Xiao Guangrong
2012-08-07 9:48 ` [PATCH v5 01/12] KVM: fix missing check for memslot flags Xiao Guangrong
2012-08-07 9:48 ` [PATCH v5 02/12] KVM: hide KVM_MEMSLOT_INVALID from userspace Xiao Guangrong
2012-08-09 18:48 ` Marcelo Tosatti
2012-08-10 2:11 ` Xiao Guangrong
2012-08-07 9:49 ` [PATCH v5 03/12] KVM: introduce gfn_to_pfn_memslot_atomic Xiao Guangrong
2012-08-09 18:50 ` Marcelo Tosatti
2012-08-10 3:22 ` Xiao Guangrong
2012-08-07 9:50 ` [PATCH v5 04/12] KVM: introduce gfn_to_hva_read/kvm_read_hva/kvm_read_hva_atomic Xiao Guangrong
2012-08-07 9:51 ` [PATCH v5 05/12] KVM: reorganize hva_to_pfn Xiao Guangrong
2012-08-10 17:51 ` Marcelo Tosatti
2012-08-11 3:11 ` Xiao Guangrong
2012-08-07 9:51 ` [PATCH v5 06/12] KVM: use 'writable' as a hint to map writable pfn Xiao Guangrong
2012-08-07 9:52 ` [PATCH v5 07/12] KVM: introduce KVM_PFN_ERR_RO_FAULT Xiao Guangrong
2012-08-07 9:52 ` [PATCH v5 08/12] KVM: introduce KVM_HVA_ERR_BAD Xiao Guangrong
2012-08-07 9:53 ` [PATCH v5 09/12] KVM: introduce KVM_HVA_ERR_RO_BAD Xiao Guangrong
2012-08-07 9:54 ` [PATCH v5 10/12] KVM: introduce readonly memslot Xiao Guangrong
2012-08-07 9:54 ` [PATCH v5 11/12] KVM: x86: introduce set_mmio_exit_info Xiao Guangrong
2012-08-10 18:03 ` Marcelo Tosatti
2012-08-11 3:13 ` Xiao Guangrong
2012-08-07 9:55 ` [PATCH v5 12/12] KVM: indicate readonly access fault Xiao Guangrong
2012-08-10 18:14 ` [PATCH v5 00/12] KVM: introduce readonly memslot Marcelo Tosatti
2012-08-11 3:36 ` Xiao Guangrong
2012-08-13 17:39 ` Marcelo Tosatti
2012-08-14 2:58 ` Xiao Guangrong
2012-08-14 15:25 ` Marcelo Tosatti
2012-08-16 5:49 ` Xiao Guangrong
2012-08-16 16:03 ` Marcelo Tosatti
2012-08-14 14:00 ` Avi Kivity [this message]
2012-08-14 15:51 ` Marcelo Tosatti
2012-08-15 10:44 ` Avi Kivity
2012-08-15 17:53 ` Marcelo Tosatti
2012-08-16 9:03 ` Avi Kivity
2012-08-16 15:57 ` Marcelo Tosatti
2012-08-16 16:17 ` Avi Kivity
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