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From: Avi Kivity <avi@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>,
	qemu-devel <qemu-devel@nongnu.org>, kvm <kvm@vger.kernel.org>,
	Liu Ping Fan <pingfank@linux.vnet.ibm.com>,
	Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v2 2/7] memory: Flush coalesced MMIO on selected region access
Date: Thu, 28 Jun 2012 19:07:40 +0300	[thread overview]
Message-ID: <4FEC814C.9040808@redhat.com> (raw)
In-Reply-To: <35d20ce2ae928e21ff715c86f854860d164ff8c9.1340814444.git.jan.kiszka@siemens.com>

On 06/27/2012 07:27 PM, Jan Kiszka wrote:
> Instead of flushing pending coalesced MMIO requests on every vmexit,
> this provides a mechanism to selectively flush when memory regions
> related to the coalesced one are accessed. This first of all includes
> the coalesced region itself but can also applied to other regions, e.g.
> of the same device, by calling memory_region_set_flush_coalesced.
> 
> +
> +void memory_region_clear_flush_coalesced(MemoryRegion *mr)
> +{
> +    qemu_flush_coalesced_mmio_buffer();
> +    mr->flush_coalesced_mmio = false;
> +}


This will clear the implicit flag set by set_coalesced, but also any
explicit flag set by set_flush_coalesced.  In some convoluted setup that
will never happen, this can cause breakage.  This can be addresses
either using two flags (or perhaps using the coalesced list for the
implicit flag) or by a comment in clear_coalesced's documentation.

-- 
error compiling committee.c: too many arguments to function



  reply	other threads:[~2012-06-28 16:08 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-27 16:27 [PATCH v2 0/7] kvm: Get coalesced MMIO flushing out of the hot-path Jan Kiszka
2012-06-27 16:27 ` [PATCH v2 1/7] i82378: Remove bogus MMIO coalescing Jan Kiszka
2012-06-27 16:27 ` [PATCH v2 2/7] memory: Flush coalesced MMIO on selected region access Jan Kiszka
2012-06-28 16:07   ` Avi Kivity [this message]
2012-06-29 16:37     ` [PATCH v3 " Jan Kiszka
2012-07-02  9:07       ` Avi Kivity
2012-07-02  9:07         ` Avi Kivity
2012-07-10 10:41         ` Jan Kiszka
2012-08-17 10:55           ` Jan Kiszka
2012-08-19  9:46             ` Avi Kivity
2012-06-27 16:27 ` [PATCH v2 3/7] memory: Use transaction_begin/commit also for single-step operations Jan Kiszka
2012-06-27 16:27 ` [PATCH v2 4/7] memory: Fold memory_region_update_topology into memory_region_transaction_commit Jan Kiszka
2012-06-27 16:27 ` [PATCH v2 5/7] memory: Flush coalesced MMIO on mapping and state changes Jan Kiszka
2012-06-27 16:27 ` [PATCH v2 6/7] VGA: Flush coalesced MMIO on related MMIO/PIO accesses Jan Kiszka
2012-06-27 16:27 ` [PATCH v2 7/7] kvm: Stop flushing coalesced MMIO on vmexit Jan Kiszka
2012-06-28 16:09 ` [PATCH v2 0/7] kvm: Get coalesced MMIO flushing out of the hot-path Avi Kivity

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