From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Brian Woods <brian.woods@amd.com>, xen-devel@lists.xen.org
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Jan Beulich <jbeulich@suse.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Subject: Re: [PATCH 2/2] x86/svm: Add checks for nested HW features
Date: Fri, 22 Dec 2017 15:15:48 +0000 [thread overview]
Message-ID: <8eb9d4df-e911-c213-4c32-dd20a54d0728@citrix.com> (raw)
In-Reply-To: <20171221152619.38079-3-brian.woods@amd.com>
On 21/12/17 15:26, Brian Woods wrote:
> Add a nestedhvm_enable() check to the existing checks for setting the
> virtual GIF and virtual VMLOAD/VMSAVE features. If it isn't a nestedhvm
> guest, do not enable the features in the VMCB.
>
> Signed-off-by: Brian Woods <brian.woods@amd.com>
Unfortunately, nestedhvm_enabled() is guaranteed to be false at the
point that construct_vmcb() is called (due the order in which
information appears while constructing the VM), which means we will
never enable these optimisations.
Combined with the observation of EFER in the pipeline, the logic to
enable/disable these optimisations needs to be in
svm_update_guest_efer(), and need to trigger when EFER.SVME changes.
~Andrew
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next prev parent reply other threads:[~2017-12-22 15:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-21 15:26 [PATCH 0/2] Various SVM Patches Brian Woods
2017-12-21 15:26 ` [PATCH 1/2] x86/svm: Add SVME checking for SVM intercepts Brian Woods
2017-12-22 4:52 ` Boris Ostrovsky
2017-12-22 15:07 ` Brian Woods
2017-12-21 15:26 ` [PATCH 2/2] x86/svm: Add checks for nested HW features Brian Woods
2017-12-22 4:55 ` Boris Ostrovsky
2017-12-22 15:15 ` Andrew Cooper [this message]
2018-01-05 15:27 ` Brian Woods
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