* [PATCH v4 0/4] CPUID-less CPU/sync_core fixes and improvements
@ 2016-12-09 18:24 Andy Lutomirski
0 siblings, 0 replies; 4+ messages in thread
From: Andy Lutomirski @ 2016-12-09 18:24 UTC (permalink / raw)
To: x86
Cc: Juergen Gross, One Thousand Gnomes, Andy Lutomirski,
Peter Zijlstra, Brian Gerst, linux-kernel, Matthew Whitehead,
Borislav Petkov, Henrique de Moraes Holschuh, Andrew Cooper,
Boris Ostrovsky, xen-devel
*** PATCHES 1 and 2 MAY BE 4.9 MATERIAL ***
Alan Cox pointed out that the 486 isn't the only supported CPU that
doesn't have CPUID. Let's clean up the mess and make everything
faster while we're at it.
Patch 1 is intended to be an easy fix: it makes sync_core() work
without CPUID on all 32-bit kernels. It should be quite safe. This
will have a negligible performance cost during boot on kernels built
for newer CPUs. With this in place, patch 2 reverts the buggy 486
check I added.
Patches 3-4 are meant to improve the situation. Patch 3 cleans up
the Intel microcode loader and the patch 4 (which depends on patch 3
to work correctly) stops using CPUID in sync_core() altogether.
Changes from v3:
- Improve sync_core() comments.
- Tidy up sync_core() asm.
Changes from v2:
- Switch to IRET-to-self and get rid of all the paravirt code.
- Further immprove the sync_core() comment.
Changes from v1:
- Fix Xen
- Add timing info to the changelog (hint: 2x speedup)
- Document patch 1 a bit better.
Andy Lutomirski (4):
x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit
kernels
Revert "x86/boot: Fail the boot if !M486 and CPUID is missing"
x86/microcode/intel: Replace sync_core() with native_cpuid()
x86/asm: Rewrite sync_core() to use IRET-to-self
arch/x86/boot/cpu.c | 6 ---
arch/x86/include/asm/processor.h | 80 +++++++++++++++++++++++++----------
arch/x86/kernel/cpu/microcode/intel.c | 26 ++++++++++--
3 files changed, 81 insertions(+), 31 deletions(-)
--
2.9.3
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v4 0/4] CPUID-less CPU/sync_core fixes and improvements
2016-12-09 18:24 Andy Lutomirski
@ 2016-12-15 18:06 ` Andy Lutomirski
2016-12-15 18:06 ` Andy Lutomirski
1 sibling, 0 replies; 4+ messages in thread
From: Andy Lutomirski @ 2016-12-15 18:06 UTC (permalink / raw)
To: Andy Lutomirski
Cc: X86 ML, One Thousand Gnomes, Borislav Petkov, linux-kernel,
Brian Gerst, Matthew Whitehead, Henrique de Moraes Holschuh,
Peter Zijlstra, xen-devel, Juergen Gross, Boris Ostrovsky,
Andrew Cooper
On Fri, Dec 9, 2016 at 10:24 AM, Andy Lutomirski <luto@kernel.org> wrote:
> *** PATCHES 1 and 2 MAY BE 4.9 MATERIAL ***
>
> Alan Cox pointed out that the 486 isn't the only supported CPU that
> doesn't have CPUID. Let's clean up the mess and make everything
> faster while we're at it.
>
Ping? Any chance of getting these in for 4.10?
--Andy
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v4 0/4] CPUID-less CPU/sync_core fixes and improvements
2016-12-09 18:24 Andy Lutomirski
2016-12-15 18:06 ` Andy Lutomirski
@ 2016-12-15 18:06 ` Andy Lutomirski
1 sibling, 0 replies; 4+ messages in thread
From: Andy Lutomirski @ 2016-12-15 18:06 UTC (permalink / raw)
To: Andy Lutomirski
Cc: Juergen Gross, One Thousand Gnomes, Peter Zijlstra, Brian Gerst,
X86 ML, linux-kernel, Matthew Whitehead, Borislav Petkov,
Henrique de Moraes Holschuh, Andrew Cooper, Boris Ostrovsky,
xen-devel
On Fri, Dec 9, 2016 at 10:24 AM, Andy Lutomirski <luto@kernel.org> wrote:
> *** PATCHES 1 and 2 MAY BE 4.9 MATERIAL ***
>
> Alan Cox pointed out that the 486 isn't the only supported CPU that
> doesn't have CPUID. Let's clean up the mess and make everything
> faster while we're at it.
>
Ping? Any chance of getting these in for 4.10?
--Andy
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v4 0/4] CPUID-less CPU/sync_core fixes and improvements
@ 2016-12-09 18:24 Andy Lutomirski
2016-12-15 18:06 ` Andy Lutomirski
2016-12-15 18:06 ` Andy Lutomirski
0 siblings, 2 replies; 4+ messages in thread
From: Andy Lutomirski @ 2016-12-09 18:24 UTC (permalink / raw)
To: x86
Cc: One Thousand Gnomes, Borislav Petkov, linux-kernel, Brian Gerst,
Matthew Whitehead, Henrique de Moraes Holschuh, Peter Zijlstra,
xen-devel, Juergen Gross, Boris Ostrovsky, Andrew Cooper,
Andy Lutomirski
*** PATCHES 1 and 2 MAY BE 4.9 MATERIAL ***
Alan Cox pointed out that the 486 isn't the only supported CPU that
doesn't have CPUID. Let's clean up the mess and make everything
faster while we're at it.
Patch 1 is intended to be an easy fix: it makes sync_core() work
without CPUID on all 32-bit kernels. It should be quite safe. This
will have a negligible performance cost during boot on kernels built
for newer CPUs. With this in place, patch 2 reverts the buggy 486
check I added.
Patches 3-4 are meant to improve the situation. Patch 3 cleans up
the Intel microcode loader and the patch 4 (which depends on patch 3
to work correctly) stops using CPUID in sync_core() altogether.
Changes from v3:
- Improve sync_core() comments.
- Tidy up sync_core() asm.
Changes from v2:
- Switch to IRET-to-self and get rid of all the paravirt code.
- Further immprove the sync_core() comment.
Changes from v1:
- Fix Xen
- Add timing info to the changelog (hint: 2x speedup)
- Document patch 1 a bit better.
Andy Lutomirski (4):
x86/asm/32: Make sync_core() handle missing CPUID on all 32-bit
kernels
Revert "x86/boot: Fail the boot if !M486 and CPUID is missing"
x86/microcode/intel: Replace sync_core() with native_cpuid()
x86/asm: Rewrite sync_core() to use IRET-to-self
arch/x86/boot/cpu.c | 6 ---
arch/x86/include/asm/processor.h | 80 +++++++++++++++++++++++++----------
arch/x86/kernel/cpu/microcode/intel.c | 26 ++++++++++--
3 files changed, 81 insertions(+), 31 deletions(-)
--
2.9.3
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-12-15 18:06 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-12-09 18:24 [PATCH v4 0/4] CPUID-less CPU/sync_core fixes and improvements Andy Lutomirski
-- strict thread matches above, loose matches on Subject: below --
2016-12-09 18:24 Andy Lutomirski
2016-12-15 18:06 ` Andy Lutomirski
2016-12-15 18:06 ` Andy Lutomirski
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.