From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Jan Beulich <JBeulich@suse.com>,
xen-devel <xen-devel@lists.xenproject.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Brian Woods <brian.woods@amd.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Subject: Re: [PATCH] SVM: limit GIF=0 region
Date: Mon, 10 Sep 2018 18:12:21 -0400 [thread overview]
Message-ID: <824e3ad6-5d72-ddce-b4ac-bd88fb8b9e26@oracle.com> (raw)
In-Reply-To: <5B96879D02000078001E6DDE@prv1-mh.provo.novell.com>
On 09/10/2018 11:02 AM, Jan Beulich wrote:
> Use EFLAGS.IF for most ordinary purposes; there's in particular no need
> to unduly defer NMI/#MC. Clear GIF only immediately before VMRUN itself.
> This has the additional advantage that svm_stgi_label now indeed marks
> the only place where GIF gets set.
>
> Note regarding the main STI placement: Quite counterintuitively the
> host's EFLAGS.IF continues to have a meaning while the guest runs; see
> PM Vol 2 section "Physical (INTR) Interrupt Masking in EFLAGS". Hence we
> need to set the flag for the duration of time being in guest context.
> However, SPEC_CTRL_ENTRY_FROM_HVM wants to be carried out with EFLAGS.IF
> clear.
>
> Note regarding the main STGI placement: It could be moved further up,
> but at present SPEC_CTRL_EXIT_TO_HVM is not NMI/#MC-safe.
>
> Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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next prev parent reply other threads:[~2018-09-10 22:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-10 15:02 [PATCH] SVM: limit GIF=0 region Jan Beulich
2018-09-10 22:12 ` Boris Ostrovsky [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-06-26 7:32 Jan Beulich
2018-06-26 8:45 ` Andrew Cooper
2018-06-26 9:52 ` Jan Beulich
2018-06-26 10:52 ` Andrew Cooper
2018-06-26 11:50 ` Jan Beulich
2018-06-26 11:53 ` Andrew Cooper
2018-06-26 11:56 ` Andrew Cooper
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