Subject: Re: [Xen-devel] [PATCH] xen/x86/pvh: Use HVM's flush_tlb_others op
To: David Vrabel <david.vrabel@citrix.com>, konrad.wilk@oracle.com
References: <1449966355-10611-1-git-send-email-boris.ostrovsky@oracle.com>
 <566ECB19.70106@citrix.com>
Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
        jbeulich@suse.com
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Message-ID: <566ECCAE.7080702@oracle.com>
Date: Mon, 14 Dec 2015 09:05:34 -0500
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On 12/14/2015 08:58 AM, David Vrabel wrote:
> On 13/12/15 00:25, Boris Ostrovsky wrote:
>> Using MMUEXT_TLB_FLUSH_MULTI doesn't buy us much since the hypervisor
>> will likely perform same IPIs as would have the guest.
>>
>> More importantly, using MMUEXT_INVLPG_MULTI may not to invalidate the
>> guest's address on remote CPU (when, for example, VCPU from another guest
>> is running there).
>>
>> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>> Suggested-by: Jan Beulich <jbeulich@suse.com>
>> Cc: stable@vger.kernel.org # 3.14+
> Applied to for-linus-4.4, thanks.  But given that PVH is experimental
> I've dropped the stable Cc.

The reason I want this to go to stable is that I will be removing access 
to MMUEXT_TLB_FLUSH_MULTI and MMUEXT_INVLPG_MULTI to PVH guests in the 
hypervisor (as part of merging HVM and PVH hypercall tables) and that 
will result in essentially unbootable PVH guests due to warnings flood.

-boris
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