linux-kernel - Re: [PATCH v3 2/5] x86/msr: Carry on after a non-"safe" MSR access fails without !panic_on

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Message-ID: <20160312153107.GA17873@gmail.com>
Date:	Sat, 12 Mar 2016 16:31:07 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Andy Lutomirski <luto@...nel.org>
Cc:	X86 ML <x86@...nel.org>, Paolo Bonzini <pbonzini@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	KVM list <kvm@...r.kernel.org>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	xen-devel <Xen-devel@...ts.xen.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v3 2/5] x86/msr: Carry on after a non-"safe" MSR access
 fails without !panic_on_oops


* Andy Lutomirski <luto@...nel.org> wrote:

> +bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup,
> +			     struct pt_regs *regs, int trapnr)
> +{
> +	WARN(1, "unsafe MSR access error: RDMSR from 0x%x",
> +	     (unsigned int)regs->cx);

Please make this WARN_ONCE(). There's no point in locking up the system with 
WARN() spam, should this trigger frequently.

> +	WARN(1, "unsafe MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x)\n",
> +	     (unsigned int)regs->cx,
> +	     (unsigned int)regs->dx, (unsigned int)regs->ax);

Ditto.

Thanks,

	Ingo