From: Paolo Bonzini <pbonzini@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: jasowang@redhat.com, vkuznets@redhat.com,
"Dr. David Alan Gilbert \(git\)" <dgilbert@redhat.com>,
qemu-devel@nongnu.org
Subject: Re: [PATCH v3 2/2] vhost: Only align sections for vhost-user
Date: Fri, 17 Jan 2020 14:58:47 +0100 [thread overview]
Message-ID: <ca54fc82-828b-158b-fadb-07abfbb9418f@redhat.com> (raw)
In-Reply-To: <20200117083232-mutt-send-email-mst@kernel.org>
On 17/01/20 14:40, Michael S. Tsirkin wrote:
> We don't really need v2 just to add a field. Compatibility is maintained
> using feature bits. Adding that is a subject for another patch.
> But I'm not sure I understand why does remote need to know about alignment.
> This patch seems to handle it locally ...
Because the remote vhost here will not be able to use the synic regions.
If it did, it would have the same overlap problem as vhost-kernel.
The alignment is needed because, even if you are mapping only [768k,1M)
of a 2M hugepage, you need to mmap [0,2M). You can then discard the
rest, but IIUC if you only mmap [768k,1M) then the kernel will fail the
mmap.
Paolo
next prev parent reply other threads:[~2020-01-17 14:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 20:24 [PATCH v3 0/2] Fix hyperv synic on vhost Dr. David Alan Gilbert (git)
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 [this message]
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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