From: "Wu, Feng" <feng.wu@intel.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
"Wu, Feng" <feng.wu@intel.com>,
"george.dunlap@eu.citrix.com" <george.dunlap@eu.citrix.com>,
"jbeulich@suse.com" <jbeulich@suse.com>,
"Zhang, Yang Z" <yang.z.zhang@intel.com>,
"keir@xen.org" <keir@xen.org>
Subject: Re: [v3 03/15] Add cmpxchg16b support for x86-64
Date: Wed, 8 Jul 2015 07:06:48 +0000 [thread overview]
Message-ID: <E959C4978C3B6342920538CF579893F0025F7808@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <558AF859.5020107@citrix.com>
> -----Original Message-----
> From: xen-devel-bounces@lists.xen.org
> [mailto:xen-devel-bounces@lists.xen.org] On Behalf Of Andrew Cooper
> Sent: Thursday, June 25, 2015 2:35 AM
> To: Wu, Feng; xen-devel@lists.xen.org
> Cc: george.dunlap@eu.citrix.com; Zhang, Yang Z; Tian, Kevin; keir@xen.org;
> jbeulich@suse.com
> Subject: Re: [Xen-devel] [v3 03/15] Add cmpxchg16b support for x86-64
>
> On 24/06/15 06:18, Feng Wu wrote:
> > This patch adds cmpxchg16b support for x86-64, so software
> > can perform 128-bit atomic write/read.
> >
> > Signed-off-by: Feng Wu <feng.wu@intel.com>
> > ---
> > v3:
> > Newly added.
> >
> > xen/include/asm-x86/x86_64/system.h | 28
> ++++++++++++++++++++++++++++
> > xen/include/xen/types.h | 5 +++++
> > 2 files changed, 33 insertions(+)
> >
> > diff --git a/xen/include/asm-x86/x86_64/system.h
> b/xen/include/asm-x86/x86_64/system.h
> > index 662813a..a910d00 100644
> > --- a/xen/include/asm-x86/x86_64/system.h
> > +++ b/xen/include/asm-x86/x86_64/system.h
> > @@ -6,6 +6,34 @@
> > (unsigned
> long)(n),sizeof(*(ptr))))
> >
> > /*
> > + * Atomic 16 bytes compare and exchange. Compare OLD with MEM, if
> > + * identical, store NEW in MEM. Return the initial value in MEM.
> > + * Success is indicated by comparing RETURN with OLD.
> > + *
> > + * This function can only be called when cpu_has_cx16 is ture.
> > + */
> > +
> > +static always_inline uint128_t __cmpxchg16b(
> > + volatile void *ptr, uint128_t old, uint128_t new)
>
> It is not nice for register scheduling taking uint128_t's by value.
> Instead, I would pass them by pointer and let the inlining sort the
> eventual references out.
>
> > +{
> > + uint128_t prev;
> > +
> > + ASSERT(cpu_has_cx16);
>
> Given that if this assertion were to fail, cmpxchg16b would fail with
> #UD, I would hand-code a asm_fixup section which in turn panics. This
> avoids a situation where non-debug builds could die with an unqualified
> #UD exception.
Is there an existing way to panic the hypervisor in assembler code, I
don't find it, it would be appreciated if you can point it out.
>
> Also, you must enforce 16-byte alignment of the memory reference, as
> described in the manual.
What should I do if the caller passes an non 16-byte alignment data
(struct iremap_entry in this case) ? Do this mean I need to define
it like this?
struct iremap_entry {
......
} __attribute__ ((aligned (16)));
Thanks,
Feng
>
> ~Andrew
>
> > +
> > + asm volatile ( "lock; cmpxchg16b %4"
> > + : "=d" (prev.high), "=a" (prev.low)
> > + : "c" (new.high), "b" (new.low),
> > + "m" (*__xg((volatile void *)ptr)),
> > + "0" (old.high), "1" (old.low)
> > + : "memory" );
> > +
> > + return prev;
> > +}
> > +
> > +#define cmpxchg16b(ptr,o,n)
> \
> > + __cmpxchg16b((ptr), *(uint128_t *)(o), *(uint128_t *)(n))
> > +
> > +/*
> > * This function causes value _o to be changed to _n at location _p.
> > * If this access causes a fault then we return 1, otherwise we return 0.
> > * If no fault occurs then _o is updated to the value we saw at _p. If this
> > diff --git a/xen/include/xen/types.h b/xen/include/xen/types.h
> > index 8596ded..30f8a44 100644
> > --- a/xen/include/xen/types.h
> > +++ b/xen/include/xen/types.h
> > @@ -47,6 +47,11 @@ typedef __u64 uint64_t;
> > typedef __u64 u_int64_t;
> > typedef __s64 int64_t;
> >
> > +typedef struct {
> > + uint64_t low;
> > + uint64_t high;
> > +} uint128_t;
> > +
> > struct domain;
> > struct vcpu;
> >
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2015-07-08 7:06 UTC|newest]
Thread overview: 155+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-24 5:18 [v3 00/15] Add VT-d Posted-Interrupts support Feng Wu
2015-06-24 5:18 ` [v3 01/15] Vt-d Posted-intterrupt (PI) design Feng Wu
2015-06-24 6:15 ` Meng Xu
2015-06-24 6:19 ` Wu, Feng
2015-07-08 7:21 ` Tian, Kevin
2015-07-08 7:29 ` Wu, Feng
2015-06-24 5:18 ` [v3 02/15] Add helper macro for X86_FEATURE_CX16 feature detection Feng Wu
2015-06-24 17:31 ` Andrew Cooper
2015-07-08 7:23 ` Tian, Kevin
2015-06-24 5:18 ` [v3 03/15] Add cmpxchg16b support for x86-64 Feng Wu
2015-06-24 18:35 ` Andrew Cooper
2015-07-08 7:06 ` Wu, Feng [this message]
2015-07-08 8:12 ` Jan Beulich
2015-07-08 8:33 ` Wu, Feng
2015-07-08 8:43 ` Jan Beulich
2015-07-08 8:50 ` Wu, Feng
2015-07-08 8:50 ` Andrew Cooper
2015-07-10 12:57 ` Jan Beulich
2015-06-24 5:18 ` [v3 04/15] iommu: Add iommu_intpost to control VT-d Posted-Interrupts feature Feng Wu
2015-06-25 9:06 ` Andrew Cooper
2015-06-25 9:47 ` Wu, Feng
2015-06-25 10:16 ` Andrew Cooper
2015-06-25 12:47 ` Wu, Feng
2015-07-08 7:30 ` Tian, Kevin
2015-06-24 5:18 ` [v3 05/15] vt-d: VT-d Posted-Interrupts feature detection Feng Wu
2015-06-25 10:21 ` Andrew Cooper
2015-06-25 13:02 ` Wu, Feng
2015-07-08 7:32 ` Tian, Kevin
2015-07-08 8:00 ` Wu, Feng
2015-06-24 5:18 ` [v3 06/15] vmx: Extend struct pi_desc to support VT-d Posted-Interrupts Feng Wu
2015-06-29 15:04 ` Andrew Cooper
2015-07-08 7:48 ` Tian, Kevin
2015-07-10 13:08 ` Jan Beulich
2015-07-15 2:40 ` Wu, Feng
2015-07-15 8:20 ` Jan Beulich
2015-07-15 8:26 ` Wu, Feng
2015-07-15 8:36 ` Jan Beulich
2015-07-15 8:43 ` Wu, Feng
2015-07-15 9:28 ` Jan Beulich
2015-07-15 9:30 ` Wu, Feng
2015-07-15 3:13 ` Wu, Feng
2015-06-24 5:18 ` [v3 07/15] vmx: Initialize VT-d Posted-Interrupts Descriptor Feng Wu
2015-06-29 15:32 ` Andrew Cooper
2015-06-30 1:46 ` Wu, Feng
2015-06-30 2:32 ` Dario Faggioli
2015-07-08 7:53 ` Tian, Kevin
2015-06-24 5:18 ` [v3 08/15] Suppress posting interrupts when 'SN' is set Feng Wu
2015-06-29 15:41 ` Andrew Cooper
2015-06-30 1:48 ` Wu, Feng
2015-07-08 9:06 ` Tian, Kevin
2015-07-08 10:11 ` Wu, Feng
2015-07-08 11:31 ` Tian, Kevin
2015-07-08 11:58 ` Wu, Feng
2015-07-10 13:20 ` Jan Beulich
2015-06-24 5:18 ` [v3 09/15] vt-d: Extend struct iremap_entry to support VT-d Posted-Interrupts Feng Wu
2015-06-29 16:04 ` Andrew Cooper
2015-06-30 1:52 ` Wu, Feng
2015-07-08 9:10 ` Tian, Kevin
2015-07-10 13:27 ` Jan Beulich
2015-06-24 5:18 ` [v3 10/15] vt-d: Add API to update IRTE when VT-d PI is used Feng Wu
2015-06-29 16:22 ` Andrew Cooper
2015-07-08 9:59 ` Tian, Kevin
2015-07-08 10:12 ` Wu, Feng
2015-07-10 14:01 ` Jan Beulich
2015-07-15 6:04 ` Wu, Feng
2015-07-15 8:24 ` Jan Beulich
2015-07-15 8:38 ` Wu, Feng
2015-07-15 8:46 ` Jan Beulich
2015-07-15 8:55 ` Wu, Feng
2015-07-15 9:32 ` Jan Beulich
2015-06-24 5:18 ` [v3 11/15] Update IRTE according to guest interrupt config changes Feng Wu
2015-06-29 16:46 ` Andrew Cooper
2015-07-08 10:22 ` Tian, Kevin
2015-07-08 10:31 ` Wu, Feng
2015-07-08 11:46 ` Tian, Kevin
2015-07-08 11:52 ` Wu, Feng
2015-07-08 11:54 ` Tian, Kevin
2015-07-10 14:23 ` Jan Beulich
2015-06-24 5:18 ` [v3 12/15] vmx: posted-interrupt handling when vCPU is blocked Feng Wu
2015-06-29 17:07 ` Andrew Cooper
2015-07-08 10:36 ` Wu, Feng
2015-07-08 10:48 ` Jan Beulich
[not found] ` <559181F9.6020106@citrix.com>
2015-06-30 2:51 ` Fwd: " Dario Faggioli
2015-06-30 2:59 ` Wu, Feng
2015-06-30 9:46 ` Dario Faggioli
2015-06-30 10:11 ` Andrew Cooper
2015-07-01 13:26 ` Dario Faggioli
2015-07-02 4:27 ` Wu, Feng
2015-07-02 8:30 ` Dario Faggioli
2015-07-02 8:58 ` Wu, Feng
2015-07-02 10:09 ` Dario Faggioli
2015-07-02 10:41 ` Wu, Feng
2015-07-02 10:30 ` Andrew Cooper
2015-07-02 10:56 ` Wu, Feng
2015-07-02 12:04 ` Dario Faggioli
2015-07-02 12:10 ` Wu, Feng
2015-07-02 12:16 ` Andrew Cooper
2015-07-02 12:38 ` Dario Faggioli
2015-07-02 12:59 ` Andrew Cooper
2015-07-03 1:33 ` Wu, Feng
2015-07-02 4:25 ` Wu, Feng
2015-07-08 11:00 ` Tian, Kevin
2015-07-08 11:02 ` Wu, Feng
2015-07-08 12:46 ` Jan Beulich
2015-07-08 13:09 ` Andrew Cooper
2015-07-08 22:49 ` Tian, Kevin
2015-07-09 7:25 ` Jan Beulich
2015-07-10 6:21 ` Wu, Feng
2015-07-10 6:32 ` Jan Beulich
2015-07-10 7:29 ` Wu, Feng
2015-07-10 8:49 ` Jan Beulich
2015-07-10 8:57 ` Wu, Feng
2015-07-08 22:31 ` Tian, Kevin
2015-06-24 5:18 ` [v3 13/15] vmx: Properly handle notification event when vCPU is running Feng Wu
2015-07-08 11:03 ` Tian, Kevin
2015-07-10 14:40 ` Jan Beulich
2015-06-24 5:18 ` [v3 14/15] Update Posted-Interrupts Descriptor during vCPU scheduling Feng Wu
[not found] ` <55918214.4030102@citrix.com>
2015-06-30 2:58 ` Fwd: " Dario Faggioli
2015-07-02 4:32 ` Wu, Feng
2015-07-02 4:34 ` Wu, Feng
2015-07-02 8:20 ` Dario Faggioli
2015-07-09 3:09 ` Wu, Feng
2015-07-09 8:18 ` Dario Faggioli
2015-07-09 11:19 ` George Dunlap
2015-07-09 11:29 ` George Dunlap
2015-07-09 11:38 ` Wu, Feng
2015-07-09 12:42 ` Dario Faggioli
2015-07-10 0:07 ` Wu, Feng
2015-07-10 12:40 ` Dario Faggioli
2015-07-10 13:47 ` Konrad Rzeszutek Wilk
2015-07-10 13:59 ` Dario Faggioli
2015-07-09 12:53 ` George Dunlap
2015-07-09 13:44 ` Jan Beulich
2015-07-09 14:18 ` Dario Faggioli
2015-07-09 14:27 ` George Dunlap
2015-07-09 14:47 ` Dario Faggioli
2015-07-10 5:59 ` Wu, Feng
2015-07-10 6:22 ` Jan Beulich
2015-07-10 11:05 ` Dario Faggioli
2015-07-14 5:44 ` Wu, Feng
2015-07-14 14:08 ` Wu, Feng
2015-07-14 14:54 ` Jan Beulich
2015-07-14 15:20 ` Dario Faggioli
2015-07-14 16:41 ` George Dunlap
2015-07-14 16:02 ` Dario Faggioli
2015-07-15 0:54 ` Wu, Feng
2015-07-17 7:46 ` Wu, Feng
2015-07-17 10:13 ` Dario Faggioli
2015-07-17 22:57 ` Wu, Feng
2015-07-18 13:43 ` Dario Faggioli
2015-07-10 0:15 ` Wu, Feng
2015-07-08 11:24 ` Tian, Kevin
2015-07-10 14:48 ` Jan Beulich
2015-06-24 5:18 ` [v3 15/15] Add a command line parameter for VT-d posted-interrupts Feng Wu
2015-07-08 11:25 ` Tian, Kevin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=E959C4978C3B6342920538CF579893F0025F7808@SHSMSX104.ccr.corp.intel.com \
--to=feng.wu@intel.com \
--cc=andrew.cooper3@citrix.com \
--cc=george.dunlap@eu.citrix.com \
--cc=jbeulich@suse.com \
--cc=keir@xen.org \
--cc=kevin.tian@intel.com \
--cc=xen-devel@lists.xen.org \
--cc=yang.z.zhang@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.