From: "Jan Beulich" <JBeulich@suse.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: Juergen Gross <jgross@suse.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 2/2] x86: use invpcid to do global flushing
Date: Fri, 09 Mar 2018 08:29:39 -0700 [thread overview]
Message-ID: <5AA2B67302000078001B0567@prv-mh.provo.novell.com> (raw)
In-Reply-To: <20180305095032.30062-3-wei.liu2@citrix.com>
>>> On 05.03.18 at 10:50, <wei.liu2@citrix.com> wrote:
> @@ -120,11 +121,24 @@ unsigned int flush_area_local(const void *va, unsigned int flags)
> else
> {
> u32 t = pre_flush();
> - unsigned long cr4 = read_cr4();
>
> - write_cr4(cr4 & ~X86_CR4_PGE);
> - barrier();
> - write_cr4(cr4);
> + if ( !cpu_has_invpcid )
> + {
> + unsigned long cr4 = read_cr4();
> +
> + write_cr4(cr4 & ~X86_CR4_PGE);
> + barrier();
> + write_cr4(cr4);
> + }
> + 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();
> + }
As just validly indicated by Jürgen, this is where my comment I
gave to one of his patches actually belongs: This is correct for
FLUSH_TLB_GLOBAL, but goes too far for FLUSH_TLB.
Jan
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next prev parent reply other threads:[~2018-03-09 15:29 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-05 9:50 [PATCH 0/2] Use invpcid Wei Liu
2018-03-05 9:50 ` [PATCH 1/2] x86: report if PCID and INVPCID are supported Wei Liu
2018-03-05 9:51 ` Juergen Gross
2018-03-05 11:20 ` Jan Beulich
2018-03-05 11:31 ` Wei Liu
2018-03-05 11:48 ` Andrew Cooper
[not found] ` <5A9D362002000078001AE74F@suse.com>
2018-03-05 11:43 ` Juergen Gross
2018-03-05 12:37 ` Jan Beulich
[not found] ` <5A9D482202000078001AE7ED@suse.com>
2018-03-05 12:49 ` Juergen Gross
2018-03-05 12:57 ` Jan Beulich
2018-03-05 13:26 ` Wei Liu
2018-03-05 9:50 ` [PATCH 2/2] x86: use invpcid to do global flushing Wei Liu
2018-03-05 9:52 ` Juergen Gross
2018-03-05 11:31 ` Jan Beulich
2018-03-05 11:50 ` Andrew Cooper
2018-03-05 12:06 ` Juergen Gross
2018-03-05 12:35 ` Andrew Cooper
2018-03-05 12:54 ` Jan Beulich
2018-03-05 12:57 ` Andrew Cooper
2018-03-05 13:11 ` Juergen Gross
2018-03-05 13:24 ` Jan Beulich
2018-03-05 13:31 ` Wei Liu
2018-03-05 13:40 ` Andrew Cooper
2018-03-05 13:44 ` Jan Beulich
2018-03-06 7:10 ` Juergen Gross
2018-03-09 15:29 ` Jan Beulich [this message]
[not found] ` <5AA2B67302000078001B0567@suse.com>
2018-03-09 18:05 ` Juergen Gross
2018-03-12 12:59 ` Jan Beulich
2018-03-12 13:10 ` Juergen Gross
2018-03-12 13:13 ` Jan Beulich
[not found] ` <5AA67CEF0200007800129C5D@suse.com>
2018-03-12 13:14 ` Juergen Gross
2018-03-13 8:07 ` Jan Beulich
[not found] ` <5AA794B402000078001B0CC7@suse.com>
2018-03-13 9:27 ` Juergen Gross
2018-03-13 9:35 ` Jan Beulich
[not found] ` <5AA7A97702000078001B0D63@suse.com>
2018-03-13 9:48 ` Juergen Gross
2018-03-13 10:22 ` Jan Beulich
2018-03-13 10:26 ` Andrew Cooper
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