From: Gleb Natapov <gleb@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: kvm@vger.kernel.org
Subject: Re: [PATCH 19/24] KVM: x86 emulator: fix in/out emulation.
Date: Wed, 10 Mar 2010 16:41:35 +0200 [thread overview]
Message-ID: <20100310144135.GW16909@redhat.com> (raw)
In-Reply-To: <4B976282.70406@redhat.com>
On Wed, Mar 10, 2010 at 11:12:34AM +0200, Avi Kivity wrote:
> On 03/09/2010 08:09 PM, Gleb Natapov wrote:
> >
> >>We don't want to enter the emulator for non-string in/out. Leftover
> >>test code?
> >>
> >No, unfortunately this is not leftover. I just don't see a way how we
> >can bypass emulator and still have emulator be able to emulate in/out
> >(for big real mode for instance). The problem is basically described in
> >the commit message. If we have function outside of emulator that does
> >in/out emulation on vcpu directly, then emulator can't use it since
> >committing shadowed registers will overwrite the result of emulation.
> >Having two different emulations (one outside of emulator and another in
> >emulator) is also problematic since when userspace returns after IO exit
> >we don't know which emulation to continue. If we want to avoid
> >instruction decoding we can fill in emulation context from exit info as
> >if instruction was already decoded and call emulator.
> >
>
> Alternatively, another entry point would be fine. in/out is a fast
> path (used for virtio for example).
>
You mean another entry point into emulator, not separate implementation
for emulated in/out and intercepted one. If yes this is what I mean by
"faking" decoding stage.
--
Gleb.
next prev parent reply other threads:[~2010-03-10 14:41 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-09 14:08 [PATCH 00/24] [RFC] emulator cleanup Gleb Natapov
2010-03-09 14:08 ` [PATCH 01/24] KVM: Remove pointer to rflags from realmode_set_cr parameters Gleb Natapov
2010-03-09 14:09 ` [PATCH 02/24] KVM: Provide callback to get/set control registers in emulator ops Gleb Natapov
2010-03-09 14:18 ` Avi Kivity
2010-03-09 14:24 ` Gleb Natapov
2010-03-09 14:09 ` [PATCH 03/24] KVM: remove realmode_lmsw function Gleb Natapov
2010-03-09 14:09 ` [PATCH 04/24] KVM: Provide current CPL as part of emulator context Gleb Natapov
2010-03-09 14:24 ` Avi Kivity
2010-03-09 14:27 ` Gleb Natapov
2010-03-09 14:09 ` [PATCH 05/24] KVM: Provide current eip " Gleb Natapov
2010-03-09 14:09 ` [PATCH 06/24] KVM: x86 emulator: fix mov r/m, sreg emulation Gleb Natapov
2010-03-09 14:09 ` [PATCH 07/24] KVM: x86 emulator: fix 0f 01 /5 emulation Gleb Natapov
2010-03-09 14:27 ` Avi Kivity
2010-03-09 14:33 ` Gleb Natapov
2010-03-09 14:34 ` Avi Kivity
2010-03-09 14:09 ` [PATCH 08/24] KVM: x86 emulator: 0f (20|21|22|23) ignore mod bits Gleb Natapov
2010-03-09 14:09 ` [PATCH 09/24] KVM: x86 emulator: inject #UD on access to non-existing CR Gleb Natapov
2010-03-09 14:09 ` [PATCH 10/24] KVM: x86 emulator: fix mov dr to inject #UD when needed Gleb Natapov
2010-03-09 14:09 ` [PATCH 11/24] KVM: x86 emulator: fix return values of syscall/sysenter/sysexit emulations Gleb Natapov
2010-03-09 14:09 ` [PATCH 12/24] KVM: x86 emulator: do not call writeback if msr access fails Gleb Natapov
2010-03-09 14:09 ` [PATCH 13/24] KVM: x86 emulator: If LOCK prefix is used dest arg should be memory Gleb Natapov
2010-03-09 14:09 ` [PATCH 14/24] KVM: x86 emulator: cleanup grp3 return value Gleb Natapov
2010-03-09 14:09 ` [PATCH 15/24] KVM: x86 emulator: Provide more callbacks for x86 emulator Gleb Natapov
2010-03-09 14:43 ` Avi Kivity
2010-03-09 16:25 ` Gleb Natapov
2010-03-09 17:22 ` Avi Kivity
2010-03-09 17:57 ` Gleb Natapov
2010-03-10 9:11 ` Avi Kivity
2010-03-09 14:09 ` [PATCH 16/24] KVM: x86 emulator: Emulate task switch in emulator.c Gleb Natapov
2010-03-09 14:09 ` [PATCH 17/24] KVM: x86 emulator: Use load_segment_descriptor() instead of kvm_load_segment_descriptor() Gleb Natapov
2010-03-09 14:09 ` [PATCH 18/24] KVM: Use task switch from emulator.c Gleb Natapov
2010-03-09 14:09 ` [PATCH 19/24] KVM: x86 emulator: fix in/out emulation Gleb Natapov
2010-03-09 14:47 ` Avi Kivity
2010-03-09 18:09 ` Gleb Natapov
2010-03-10 9:12 ` Avi Kivity
2010-03-10 14:41 ` Gleb Natapov [this message]
2010-03-09 14:09 ` [PATCH 20/24] KVM: x86 emulator: Move string pio emulation into emulator.c Gleb Natapov
2010-03-09 14:09 ` [PATCH 21/24] KVM: x86 emulator: remove saved_eip Gleb Natapov
2010-03-09 14:09 ` [PATCH 22/24] KVM: x86 emulator: restart string instruction without going back to a guest Gleb Natapov
2010-03-09 14:50 ` Avi Kivity
2010-03-09 18:11 ` Gleb Natapov
2010-03-10 2:30 ` Takuya Yoshikawa
2010-03-10 9:06 ` Gleb Natapov
2010-03-10 9:12 ` Takuya Yoshikawa
2010-03-10 9:14 ` Avi Kivity
2010-03-10 9:15 ` Gleb Natapov
2010-03-10 10:08 ` Takuya Yoshikawa
2010-03-10 13:48 ` Gleb Natapov
2010-03-11 9:58 ` Takuya Yoshikawa
2010-03-11 10:07 ` Gleb Natapov
2010-03-10 9:13 ` Avi Kivity
2010-03-09 14:09 ` [PATCH 23/24] KVM: x86 emulator: introduce pio in string read ahead Gleb Natapov
2010-03-09 14:09 ` [PATCH 24/24] KVM: small kvm_arch_vcpu_ioctl_run() cleanup Gleb Natapov
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=20100310144135.GW16909@redhat.com \
--to=gleb@redhat.com \
--cc=avi@redhat.com \
--cc=kvm@vger.kernel.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox