Re: [PATCH v2 4/6] xen/x86: disable global pages for domains with XPTI active

From: Juergen Gross <jgross@suse.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: andrew.cooper3@citrix.com, wei.liu2@citrix.com,
	xen-devel@lists.xenproject.org,
	Dario Faggioli <dfaggioli@suse.com>
Subject: Re: [PATCH v2 4/6] xen/x86: disable global pages for domains with XPTI active
Date: Fri, 9 Mar 2018 15:40:02 +0100	[thread overview]
Message-ID: <fcc57ee2-68dc-a6d4-44be-4200b85bb33d@suse.com> (raw)
In-Reply-To: <5AA15F9702000078001AFDDF@prv-mh.provo.novell.com>

On 08/03/18 16:06, Jan Beulich wrote:
>>>> On 02.03.18 at 09:14, <jgross@suse.com> wrote:
>> @@ -123,22 +142,14 @@ unsigned int flush_area_local(const void *va, unsigned int flags)
>>              u32 t = pre_flush();
>>  
>>              if ( !cpu_has_invpcid )
>> -            {
>> -                unsigned long cr4 = read_cr4();
>> -
>> -                write_cr4(cr4 & ~X86_CR4_PGE);
>> -                barrier();
>> -                write_cr4(cr4);
>> -            }
>> +                do_flush_tlb(0);
>>              else
>> -            {
>>                  /*
>>                   * Using invpcid to flush all mappings works
>>                   * regardless of whether PCID is enabled or not.
>>                   * It is faster than read-modify-write CR4.
>>                   */
>>                  invpcid_flush_all();
>> -            }
> 
> Btw, this is correct for FLUSH_TLB_GLOBAL, but goes too far for
> FLUSH_TLB.

You are aware that my patches didn't change anything in this regard?

Juergen

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel