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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>,
	Xen-devel <xen-devel@lists.xen.org>
Cc: Brian Woods <brian.woods@amd.com>,
	Jan Beulich <JBeulich@suse.com>,
	Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Subject: Re: [PATCH] x86/svm: Fixes to OS Visible Workaround handling
Date: Tue, 21 Aug 2018 11:09:22 -0400	[thread overview]
Message-ID: <a0f81b84-d016-8ca8-ec23-bea7aeb045b7@oracle.com> (raw)
In-Reply-To: <1534352869-27401-1-git-send-email-andrew.cooper3@citrix.com>

On 08/15/2018 01:07 PM, Andrew Cooper wrote:
> OSVW data is technically per-cpu, but it is the firmwares reponsibility to
> make it equivelent on each cpu.  A guests OSVW data is sources from global
> data in Xen, clearly making it per-domain data rather than per-vcpu data.
>
> Move the data from struct arch_svm_struct to struct svm_domain, and call
> svm_guest_osvw_init() from svm_domain_initialise() instead of
> svm_vcpu_initialise().
>
> In svm_guest_osvw_init(), reading osvw_length and osvw_status must be done
> under the osvw_lock to avoid observing mismatched values.  The guests view of
> osvw_length also needs clipping at 64 as we only offer one status register (To
> date, 5 is the maximum index defined AFAICT).  Avoid opencoding max().


Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

We should probably emit a warning when MSR_AMD_OSVW_ID_LENGTH reports
more than 64 bits in svm_host_osvw_init().


-boris

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      reply	other threads:[~2018-08-21 15:09 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-15 17:07 [PATCH] x86/svm: Fixes to OS Visible Workaround handling Andrew Cooper
2018-08-21 15:09 ` Boris Ostrovsky [this message]

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