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From: Anthony PERARD <anthony.perard@citrix.com>
To: Igor Druzhinin <igor.druzhinin@citrix.com>
Cc: xen-devel@lists.xenproject.org, sstabellini@kernel.org,
	qemu-devel@nongnu.org, ross.lagerwall@citrix.com
Subject: Re: [PATCH] xen/pt: use address_space_memory object for memory region hooks
Date: Tue, 17 Apr 2018 15:15:18 +0100	[thread overview]
Message-ID: <20180417141518.GM2208@perard> (raw)
In-Reply-To: <1523049683-11782-1-git-send-email-igor.druzhinin@citrix.com>

On Fri, Apr 06, 2018 at 10:21:23PM +0100, Igor Druzhinin wrote:
> Commit 99605175c (xen-pt: Fix PCI devices re-attach failed) introduced
> a subtle bug. As soon as the guest switches off Bus Mastering on the
> device it immediately causes all the BARs be unmapped due to the DMA
> address space of the device being changed. This is undesired behavior
> because the guest may try to communicate with the device after that
> which triggers the following errors in the logs:
> 
> [00:05.0] xen_pt_bar_read: Error: Should not read BAR through QEMU. @0x0000000000000200
> [00:05.0] xen_pt_bar_write: Error: Should not write BAR through QEMU. @0x0000000000000200
> 
> The issue that the original patch tried to workaround (uneven number of
> region_add/del calls on device attach/detach) was fixed in later QEMU
> versions.

Do you know when the issue was fixed?

-- 
Anthony PERARD

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WARNING: multiple messages have this Message-ID (diff)
From: Anthony PERARD <anthony.perard@citrix.com>
To: Igor Druzhinin <igor.druzhinin@citrix.com>
Cc: xen-devel@lists.xenproject.org, qemu-devel@nongnu.org,
	sstabellini@kernel.org, ross.lagerwall@citrix.com
Subject: Re: [Qemu-devel] [PATCH] xen/pt: use address_space_memory object for memory region hooks
Date: Tue, 17 Apr 2018 15:15:18 +0100	[thread overview]
Message-ID: <20180417141518.GM2208@perard> (raw)
In-Reply-To: <1523049683-11782-1-git-send-email-igor.druzhinin@citrix.com>

On Fri, Apr 06, 2018 at 10:21:23PM +0100, Igor Druzhinin wrote:
> Commit 99605175c (xen-pt: Fix PCI devices re-attach failed) introduced
> a subtle bug. As soon as the guest switches off Bus Mastering on the
> device it immediately causes all the BARs be unmapped due to the DMA
> address space of the device being changed. This is undesired behavior
> because the guest may try to communicate with the device after that
> which triggers the following errors in the logs:
> 
> [00:05.0] xen_pt_bar_read: Error: Should not read BAR through QEMU. @0x0000000000000200
> [00:05.0] xen_pt_bar_write: Error: Should not write BAR through QEMU. @0x0000000000000200
> 
> The issue that the original patch tried to workaround (uneven number of
> region_add/del calls on device attach/detach) was fixed in later QEMU
> versions.

Do you know when the issue was fixed?

-- 
Anthony PERARD

  parent reply	other threads:[~2018-04-17 14:15 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-06 21:21 [Qemu-devel] [PATCH] xen/pt: use address_space_memory object for memory region hooks Igor Druzhinin
2018-04-17 13:58 ` Igor Druzhinin
2018-04-17 13:58   ` [Qemu-devel] " Igor Druzhinin
2018-04-17 14:15 ` Anthony PERARD [this message]
2018-04-17 14:15   ` Anthony PERARD
2018-04-17 14:18   ` Igor Druzhinin
2018-04-17 14:18     ` [Qemu-devel] " Igor Druzhinin
2018-04-17 14:37     ` Anthony PERARD
2018-04-17 14:37     ` Anthony PERARD
2018-04-17 14:29   ` Igor Druzhinin
2018-04-17 14:29     ` [Qemu-devel] " Igor Druzhinin
  -- strict thread matches above, loose matches on Subject: below --
2018-04-06 21:21 Igor Druzhinin

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