Re: [Xen-devel] traps.c:3227: GPF (0000): ffff82d080194a4d -> ffff82d080239d85 and other dom0 induced log messages

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 26.06.15 at 17:41, <linux@xxxxxxxxxxxxxx> wrote:
> from 3.16 to 3.19 we gained a lot of these, if i remember correctly 
> related to
> perf being enabled in the kernel:
> 
> +   traps.c:2655:d0v0 Domain attempted WRMSR 00000000c0000081 from 
> 0xe023e00800000000 to 0x0023001000000000.
> +   traps.c:2655:d0v0 Domain attempted WRMSR 00000000c0000082 from 
> 0xffff82d0bffff000 to 0xffffffff81bc2670.
> +   traps.c:2655:d0v0 Domain attempted WRMSR 00000000c0000083 from 
> 0xffff82d0bffff020 to 0xffffffff81bc4630.

These are the SYSCALL (STAR) MSRs, which the kernel has no business
touching when running on Xen.

> from 3.19 to 4.0 we gained:
> +   d0 attempted to change d0v0's CR4 flags 00000660 -> 00000760
> +   d0 attempted to change d0v1's CR4 flags 00000660 -> 00000760
> +   d0 attempted to change d0v2's CR4 flags 00000660 -> 00000760
> +   d0 attempted to change d0v3's CR4 flags 00000660 -> 00000760
> +   d0 attempted to change d0v4's CR4 flags 00000660 -> 00000760
> +   d0 attempted to change d0v5's CR4 flags 00000660 -> 00000760

This is X86_CR4_PCE - not sure how to properly handle that.
Andrew, you're fiddling with the CR4 handling right now anyway -
any thoughts?

> and from 4.0 to 4.1 we gained the ones you were interested in:
> +   traps.c:3227: GPF (0000): ffff82d080194a4d -> ffff82d080239d85
> +   traps.c:3227: GPF (0000): ffff82d080194a4d -> ffff82d080239d85
> +   traps.c:3227: GPF (0000): ffff82d080194a4d -> ffff82d080239d85
> +   traps.c:3227: GPF (0000): ffff82d080194a4d -> ffff82d080239d85
> +   traps.c:3227: GPF (0000): ffff82d080194a4d -> ffff82d080239d85
> +   traps.c:3227: GPF (0000): ffff82d080194a4d -> ffff82d080239d85

For these to be meaningful you need to translate them to symbolic
addresses. (And yes, we should see to make the code print them
in a more useful manner.)

Jan


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