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From: "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>
To: qemu-devel@nongnu.org, vkuznets@redhat.com, mst@redhat.com,
	jasowang@redhat.com, pbonzini@redhat.com
Subject: [PATCH v3 0/2] Fix hyperv synic on vhost
Date: Thu, 16 Jan 2020 20:24:12 +0000
Message-ID: <20200116202414.157959-1-dgilbert@redhat.com> (raw)

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Hyperv's synic (that we emulate) is a feature that allows the guest
to place some magic (4k) pages of RAM anywhere it likes in GPA.
This confuses vhost's RAM section merging when these pages
land over the top of hugepages.

This v3 takes a different approach to v2 and v1.
It avoids doing the hugepage alignment except for vhost-user:

  a) Vhost kernel : doesn't need alignment, it's turned off
     synic won't cause a problem.

  b) vhost user : Already filters out anything without an fd
     synic won't cause a problem.

(Not tried vhost-user yet, it currently seems broken even without this).

This might also cause some other reported problems with vga
pages causing similar issues.

bz: https://bugzilla.redhat.com/show_bug.cgi?id=1779041

Dr. David Alan Gilbert (2):
  vhost: Add names to section rounded warning
  vhost: Only align sections for vhost-user

 hw/virtio/vhost.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)


             reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16 20:24 Dr. David Alan Gilbert (git) [this message]
2020-01-16 20:24 ` [PATCH v3 1/2] vhost: Add names to section rounded warning Dr. David Alan Gilbert (git)
2020-01-16 20:24 ` [PATCH v3 2/2] vhost: Only align sections for vhost-user Dr. David Alan Gilbert (git)
2020-01-17 12:52   ` Paolo Bonzini
2020-01-17 13:40     ` Michael S. Tsirkin
2020-01-17 13:58       ` Paolo Bonzini
2020-01-17 14:25         ` Michael S. Tsirkin
2020-01-17 15:06           ` Paolo Bonzini
2020-01-17 15:10         ` Dr. David Alan Gilbert
2020-01-17  0:24 ` [PATCH v3 0/2] Fix hyperv synic on vhost no-reply
2020-01-17 12:47   ` Dr. David Alan Gilbert

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