From: Jan Kiszka <jan.kiszka@siemens.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>, kvm <kvm@vger.kernel.org>,
"Joel Schopp" <joel.schopp@amd.com>
Subject: Re: [PATCH v2] KVM: SVM: Sync g_pat with guest-written PAT value
Date: Tue, 21 Apr 2015 13:56:52 +0200 [thread overview]
Message-ID: <55363B04.20108@siemens.com> (raw)
In-Reply-To: <5536354F.5000503@redhat.com>
On 2015-04-21 13:32, Paolo Bonzini wrote:
> Basically it's an optimization. The guest can set the UC memory type on
> PCI BARs that are actually backed by RAM in QEMU, and then accesses to
> these BARs will be unnecessarily slow. It would be particularly bad if,
> for example, access to ivshmem were slowed down because the guest PAT
> says the memory is uncacheable.
ivshmem is pv anyway - why shouldn't the guest driver take this room for
optimization into account and ask for a cached mapping?
Is that that only use case?
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2015-04-21 11:57 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-13 5:16 KVM: How does is PAT emulation supposed to work? Jan Kiszka
2015-04-13 6:58 ` [RFC][PATCH] KVM: SVM: Sync g_pat with guest-written PAT value Jan Kiszka
2015-04-17 16:59 ` Radim Krčmář
2015-04-20 16:14 ` Radim Krčmář
2015-04-20 17:16 ` Radim Krčmář
2015-04-20 17:21 ` Jan Kiszka
2015-04-20 17:33 ` Radim Krčmář
2015-04-20 17:37 ` Jan Kiszka
2015-04-20 17:45 ` Jan Kiszka
2015-04-20 18:33 ` Radim Krčmář
2015-04-20 18:41 ` Jan Kiszka
2015-04-21 12:10 ` Radim Krčmář
2015-04-21 12:11 ` Paolo Bonzini
2015-04-20 17:22 ` Radim Krčmář
2015-04-20 17:25 ` [PATCH v2] " Jan Kiszka
2015-04-20 17:35 ` Radim Krčmář
2015-04-21 11:09 ` Paolo Bonzini
2015-04-21 11:25 ` Jan Kiszka
2015-04-21 11:32 ` Paolo Bonzini
2015-04-21 11:56 ` Jan Kiszka [this message]
2015-04-21 12:12 ` Paolo Bonzini
2015-04-21 12:21 ` Radim Krčmář
2015-05-24 15:28 ` Jan Kiszka
2016-02-09 19:25 ` Jan Kiszka
2015-04-17 16:43 ` KVM: How does is PAT emulation supposed to work? Radim Krčmář
2015-04-17 17:12 ` Jan Kiszka
2015-04-17 20:28 ` Radim Krčmář
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=55363B04.20108@siemens.com \
--to=jan.kiszka@siemens.com \
--cc=joel.schopp@amd.com \
--cc=kvm@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=rkrcmar@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.