Messages in this thread | | | Date | Wed, 15 Sep 2021 17:27:35 -0700 | From | Ricardo Neri <> | Subject | Re: [PATCH] x86/umip: Downgrade warning messages to debug loglevel |
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On Wed, Sep 15, 2021 at 04:46:20PM +0200, Borislav Petkov wrote: > 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)))
FWIW, Reviewed-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Thanks and BR, Ricardo
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