From: "Jürgen Groß" <jgross@suse.com>
To: peterz@infradead.org, Marco Elver <elver@google.com>
Cc: syzbot <syzbot+8db9e1ecde74e590a657@syzkaller.appspotmail.com>,
fenghua.yu@intel.com, yu-cheng.yu@intel.com, tony.luck@intel.com,
dave.hansen@linux.intel.com, syzkaller-bugs@googlegroups.com,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
virtualization@lists.linux-foundation.org, mingo@redhat.com,
bp@alien8.de, hpa@zytor.com, tglx@linutronix.de, x86@kernel.org
Subject: Re: [PATCH] x86/paravirt: Add missing noinstr to arch_local*() helpers
Date: Wed, 5 Aug 2020 16:17:07 +0200 [thread overview]
Message-ID: <b4d46726-d343-f347-c044-06c6e815076a@suse.com> (raw)
In-Reply-To: <20200805141237.GS2674@hirez.programming.kicks-ass.net>
On 05.08.20 16:12, peterz@infradead.org wrote:
> On Wed, Aug 05, 2020 at 03:59:40PM +0200, Marco Elver wrote:
>> On Wed, Aug 05, 2020 at 03:42PM +0200, peterz@infradead.org wrote:
>
>>> Shouldn't we __always_inline those? They're going to be really small.
>>
>> I can send a v2, and you can choose. For reference, though:
>>
>> ffffffff86271ee0 <arch_local_save_flags>:
>> ffffffff86271ee0: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
>> ffffffff86271ee5: 48 83 3d 43 87 e4 01 cmpq $0x0,0x1e48743(%rip) # ffffffff880ba630 <pv_ops+0x120>
>> ffffffff86271eec: 00
>> ffffffff86271eed: 74 0d je ffffffff86271efc <arch_local_save_flags+0x1c>
>> ffffffff86271eef: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
>> ffffffff86271ef4: ff 14 25 30 a6 0b 88 callq *0xffffffff880ba630
>> ffffffff86271efb: c3 retq
>> ffffffff86271efc: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
>> ffffffff86271f01: 0f 0b ud2
>
>> ffffffff86271a90 <arch_local_irq_restore>:
>> ffffffff86271a90: 53 push %rbx
>> ffffffff86271a91: 48 89 fb mov %rdi,%rbx
>> ffffffff86271a94: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
>> ffffffff86271a99: 48 83 3d 97 8b e4 01 cmpq $0x0,0x1e48b97(%rip) # ffffffff880ba638 <pv_ops+0x128>
>> ffffffff86271aa0: 00
>> ffffffff86271aa1: 74 11 je ffffffff86271ab4 <arch_local_irq_restore+0x24>
>> ffffffff86271aa3: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
>> ffffffff86271aa8: 48 89 df mov %rbx,%rdi
>> ffffffff86271aab: ff 14 25 38 a6 0b 88 callq *0xffffffff880ba638
>> ffffffff86271ab2: 5b pop %rbx
>> ffffffff86271ab3: c3 retq
>> ffffffff86271ab4: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
>> ffffffff86271ab9: 0f 0b ud2
>
>
> Blergh, that's abysmall. In part I suspect because you have
> CONFIG_PARAVIRT_DEBUG, let me try and untangle that PV macro maze.
>
Probably. I have found the following in my kernel:
fffffff81540a5f <arch_local_save_flags>:
ffffffff81540a5f: ff 14 25 40 a4 23 82 callq *0xffffffff8223a440
ffffffff81540a66: c3 retq
Juergen
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next prev parent reply other threads:[~2020-08-05 14:17 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <0000000000007d3b2d05ac1c303e@google.com>
[not found] ` <20200805132629.GA87338@elver.google.com>
2020-08-05 13:42 ` [PATCH] x86/paravirt: Add missing noinstr to arch_local*() helpers peterz
[not found] ` <20200805135940.GA156343@elver.google.com>
2020-08-05 14:12 ` peterz
2020-08-05 14:17 ` Jürgen Groß [this message]
2020-08-05 14:17 ` peterz
[not found] ` <CANpmjNN6FWZ+MsAn3Pj+WEez97diHzqF8hjONtHG15C2gSpSgw@mail.gmail.com>
[not found] ` <CANpmjNNy3XKQqgrjGPPKKvXhAoF=mae7dk8hmoS4k4oNnnB=KA@mail.gmail.com>
[not found] ` <20200806074723.GA2364872@elver.google.com>
2020-08-06 11:32 ` peterz
[not found] ` <20200806131702.GA3029162@elver.google.com>
[not found] ` <CANpmjNNqt8YrCad4WqgCoXvH47pRXtSLpnTKhD8W8+UpoYJ+jQ@mail.gmail.com>
[not found] ` <CANpmjNO860SHpNve+vaoAOgarU1SWy8o--tUWCqNhn82OLCiew@mail.gmail.com>
2020-08-07 9:24 ` Jürgen Groß
[not found] ` <20200807095032.GA3528289@elver.google.com>
2020-08-07 10:35 ` Jürgen Groß
[not found] ` <20200807113838.GA3547125@elver.google.com>
2020-08-07 12:04 ` Jürgen Groß
[not found] ` <CANpmjNPau_DEYadey9OL+iFZKEaUTqnFnyFs1dU12o00mg7ofA@mail.gmail.com>
[not found] ` <20200807151903.GA1263469@elver.google.com>
[not found] ` <CANpmjNM1jASqCFYZpteVrZCa2V2D_DbXaqvoCV_Ac2boYfDXnQ@mail.gmail.com>
2020-08-11 7:04 ` Jürgen Groß
2020-08-11 7:41 ` Peter Zijlstra
2020-08-11 7:57 ` Jürgen Groß
2020-08-11 8:12 ` Peter Zijlstra
2020-08-11 8:18 ` Jürgen Groß
2020-08-11 8:38 ` Jürgen Groß
2020-08-11 9:20 ` peterz
2020-08-11 9:46 ` peterz
2020-08-11 20:17 ` peterz
[not found] ` <20200812080650.GA3894595@elver.google.com>
2020-08-12 8:18 ` peterz
2020-08-12 8:57 ` peterz
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