linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Tim Chen <tim.c.chen@linux.intel.com>
To: mingo@kernel.org, hpa@zytor.com, tglx@linutronix.de,
	torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
	dwmw@amazon.co.uk, peterz@infradead.org,
	linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/pti] x86/speculation: Use IBRS if available before calling into firmware
Date: Fri, 16 Feb 2018 10:44:06 -0800	[thread overview]
Message-ID: <c77b3da9-136d-9988-119f-e94c86fd34a3@linux.intel.com> (raw)
In-Reply-To: <tip-670c3e8da87fa4046a55077b1409cf250865a203@git.kernel.org>

On 02/11/2018 11:19 AM, tip-bot for David Woodhouse wrote:
		\
>  })
> diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
> index 300cc15..788c4da 100644
> --- a/arch/x86/include/asm/nospec-branch.h
> +++ b/arch/x86/include/asm/nospec-branch.h
> @@ -162,17 +162,36 @@ static inline void vmexit_fill_RSB(void)
>  #endif
>  }
>  
> +#define alternative_msr_write(_msr, _val, _feature)		\
> +	asm volatile(ALTERNATIVE("",				\
> +				 "movl %[msr], %%ecx\n\t"	\
> +				 "movl %[val], %%eax\n\t"	\
> +				 "movl $0, %%edx\n\t"		\
> +				 "wrmsr",			\
> +				 _feature)			\
> +		     : : [msr] "i" (_msr), [val] "i" (_val)	\
> +		     : "eax", "ecx", "edx", "memory")
> +

I encountered hang on a machine but not others when using the above
macro.  It is probably an alignment thing with ALTERNATIVE as the problem went
away after I made the change below:

Tim

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 8f2ff74..0f65bd2 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -148,6 +148,7 @@ extern char __indirect_thunk_end[];
 
 #define alternative_msr_write(_msr, _val, _feature)            \
        asm volatile(ALTERNATIVE("",                            \
+                               ".align 16\n\t"                \
                                "movl %[msr], %%ecx\n\t"       \
                                "movl %[val], %%eax\n\t"       \
                                "movl $0, %%edx\n\t"           \

  parent reply	other threads:[~2018-02-16 18:44 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-10 23:39 [PATCH v2 0/6] Spectre v2 updates David Woodhouse
2018-02-10 23:39 ` [PATCH v2 1/6] x86/speculation: Update Speculation Control microcode blacklist David Woodhouse
2018-02-11 12:08   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-02-12  9:50   ` [PATCH v2 1/6] " Darren Kenny
2018-02-12 14:16   ` David Woodhouse
2018-02-12 14:32     ` Thomas Gleixner
2018-02-10 23:39 ` [PATCH v2 2/6] Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()" David Woodhouse
2018-02-11 12:09   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-02-13  8:58   ` tip-bot for David Woodhouse
2018-02-13  9:41     ` Peter Zijlstra
2018-02-13 11:28       ` Ingo Molnar
2018-02-13 13:28         ` Peter Zijlstra
2018-02-13 13:38           ` Ingo Molnar
2018-02-13 15:26           ` [tip:x86/pti] x86/speculation: Add <asm/msr-index.h> dependency tip-bot for Peter Zijlstra
2018-02-15  0:28           ` tip-bot for Peter Zijlstra
2018-02-10 23:39 ` [PATCH v2 3/6] KVM: x86: Reduce retpoline performance impact in slot_handle_level_range() David Woodhouse
2018-02-11 12:09   ` [tip:x86/pti] KVM/x86: Reduce retpoline performance impact in slot_handle_level_range(), by always inlining iterator helper methods tip-bot for David Woodhouse
2018-02-13  8:58   ` tip-bot for David Woodhouse
2018-02-10 23:39 ` [PATCH v2 4/6] X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs David Woodhouse
2018-02-11 12:10   ` [tip:x86/pti] " tip-bot for KarimAllah Ahmed
2018-02-13  8:59   ` tip-bot for KarimAllah Ahmed
2018-02-10 23:39 ` [PATCH v2 5/6] KVM/nVMX: Set the CPU_BASED_USE_MSR_BITMAPS if we have a valid L02 MSR bitmap David Woodhouse
2018-02-11 10:19   ` Ingo Molnar
     [not found]     ` <1518345844.3677.365.camel@amazon.co.uk>
2018-02-11 10:55       ` Ingo Molnar
2018-02-11 12:10   ` [tip:x86/pti] " tip-bot for KarimAllah Ahmed
2018-02-13  8:59   ` tip-bot for KarimAllah Ahmed
2018-02-10 23:39 ` [PATCH v2 6/6] x86/speculation: Use IBRS if available before calling into firmware David Woodhouse
2018-02-11 11:46   ` Ingo Molnar
2018-02-11 10:41 ` [PATCH v2 0/6] Spectre v2 updates Ingo Molnar
2018-02-11 15:19 ` [PATCH v2.1] x86/speculation: Use IBRS if available before calling into firmware David Woodhouse
2018-02-11 18:50   ` [PATCH] x86/speculation: Clean up various Spectre related details Ingo Molnar
2018-02-11 19:25     ` David Woodhouse
2018-02-11 19:43       ` Ingo Molnar
2018-02-12 15:30         ` David Woodhouse
2018-02-13  8:04           ` Ingo Molnar
2018-02-11 19:19   ` [tip:x86/pti] x86/speculation: Use IBRS if available before calling into firmware tip-bot for David Woodhouse
2018-02-12  5:59     ` afzal mohammed
2018-02-12 16:30       ` David Woodhouse
2018-02-12 10:22     ` Ingo Molnar
2018-02-12 11:50       ` Peter Zijlstra
2018-02-12 12:27         ` David Woodhouse
2018-02-12 13:06           ` Peter Zijlstra
2018-02-13  7:58           ` Ingo Molnar
2018-02-12 12:28         ` Peter Zijlstra
2018-02-12 16:13       ` Dave Hansen
2018-02-12 16:58         ` Peter Zijlstra
2018-02-13  7:55           ` Ingo Molnar
2018-02-14  1:49             ` Tim Chen
2018-02-14  8:56               ` Peter Zijlstra
2018-02-14  8:57                 ` Peter Zijlstra
2018-02-14 19:20                 ` Tim Chen
2018-02-14 23:19                   ` Ingo Molnar
2018-02-15  2:01                     ` Tim Chen
2018-02-14  9:31               ` [PATCH] watchdog: hpwdt: Remove spinlock acquire and BIOS calls from NMI context Ingo Molnar
2018-02-14  9:38                 ` Peter Zijlstra
2018-02-14 10:39                   ` Ingo Molnar
2018-02-14  9:44                 ` Borislav Petkov
2018-02-14 18:13                   ` Jerry Hoemann
2018-02-14 23:17                     ` Ingo Molnar
2018-02-15 17:44                       ` Jerry Hoemann
2018-02-15 19:02                         ` Ingo Molnar
2018-02-15 19:48                         ` Peter Zijlstra
2018-02-16 18:44     ` Tim Chen [this message]
2018-02-16 19:16       ` [tip:x86/pti] x86/speculation: Use IBRS if available before calling into firmware David Woodhouse
2018-02-16 23:46         ` Tim Chen
2018-02-17 10:26           ` Ingo Molnar
2018-02-19  9:20             ` Peter Zijlstra
2018-02-19  9:29               ` David Woodhouse
2018-02-19  9:39                 ` Ingo Molnar
2018-02-19  9:44                   ` David Woodhouse
2018-02-19 10:08                 ` Peter Zijlstra
2018-02-19  9:36               ` Ingo Molnar
2018-02-12  8:27 ` [PATCH v2 0/6] Spectre v2 updates Paolo Bonzini
2018-02-13  7:59   ` Ingo Molnar
2018-02-19 10:50 [PATCH v3 1/4] x86/speculation: Use IBRS if available before calling into firmware David Woodhouse
2018-02-20 10:29 ` [tip:x86/pti] " tip-bot for David Woodhouse

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=c77b3da9-136d-9988-119f-e94c86fd34a3@linux.intel.com \
    --to=tim.c.chen@linux.intel.com \
    --cc=dwmw@amazon.co.uk \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).