Messages in this thread Patch in this message | | | Date | Wed, 15 Sep 2021 16:46:20 +0200 | From | Borislav Petkov <> | Subject | [PATCH] x86/umip: Downgrade warning messages to debug loglevel |
| |
On Wed, Sep 15, 2021 at 04:34:10AM -0700, Ricardo Neri wrote: > The goal at the time was encourage users to report bugs on the > applications and eventually have them fixed. It also meant to warn users > about degraded performance due to emulation. To my knowledge, no one has > reported the latter thus far.
Probably because people do not even get to need UMIP a whole lot, apparently.
> Since after almost 4 years, performance degradation does not seem to be a > concern, I think it is sensible to remove the warnings.
Yap.
> They could also be salvaged by converting them to umiip_pr_debug(), just > to err on the cautious side without having to add a new command line > argument.
Yap, that's a good idea too:
--- From: Borislav Petkov <bp@suse.de> Date: Wed, 15 Sep 2021 16:39:18 +0200 Subject: [PATCH] x86/umip: Downgrade warning messages to debug loglevel MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
After four years in the wild, those have not fullfilled their initial purpose of pushing people to fix their software to not use UMIP-emulated instructions, and to warn users about the degraded emulation performance.
Yet, the only thing that "degrades" performance is overflowing dmesg with those:
[Di Sep 7 00:24:05 2021] umip_printk: 1345 callbacks suppressed [Di Sep 7 00:24:05 2021] umip: someapp.exe[29231] ip:14064cdba sp:11b7c0: SIDT instruction cannot be used by applications. [Di Sep 7 00:24:05 2021] umip: someapp.exe[29231] ip:14064cdba sp:11b7c0: For now, expensive software emulation returns the result. ... [Di Sep 7 00:26:06 2021] umip_printk: 2227 callbacks suppressed [Di Sep 7 00:26:06 2021] umip: someapp.exe[29231] ip:14064cdba sp:11b940: SIDT instruction cannot be used by applications.
and users don't really care about that - they just want to play their games in wine.
So convert those to debug loglevel - in case someone is still interested in them, someone can boot with "debug" on the kernel cmdline.
Reported-by: Marcus Rückert <mrueckert@suse.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210907200454.30458-1-bp@alien8.de --- arch/x86/kernel/umip.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c index 576b47e7523d..5a4b21389b1d 100644 --- a/arch/x86/kernel/umip.c +++ b/arch/x86/kernel/umip.c @@ -92,8 +92,8 @@ static const char * const umip_insns[5] = { #define umip_pr_err(regs, fmt, ...) \ umip_printk(regs, KERN_ERR, fmt, ##__VA_ARGS__) -#define umip_pr_warn(regs, fmt, ...) \ - umip_printk(regs, KERN_WARNING, fmt, ##__VA_ARGS__) +#define umip_pr_debug(regs, fmt, ...) \ + umip_printk(regs, KERN_DEBUG, fmt, ##__VA_ARGS__) /** * umip_printk() - Print a rate-limited message @@ -361,10 +361,10 @@ bool fixup_umip_exception(struct pt_regs *regs) if (umip_inst < 0) return false; - umip_pr_warn(regs, "%s instruction cannot be used by applications.\n", + umip_pr_debug(regs, "%s instruction cannot be used by applications.\n", umip_insns[umip_inst]); - umip_pr_warn(regs, "For now, expensive software emulation returns the result.\n"); + umip_pr_debug(regs, "For now, expensive software emulation returns the result.\n"); if (emulate_umip_insn(&insn, umip_inst, dummy_data, &dummy_data_size, user_64bit_mode(regs))) -- 2.29.2
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
| |