Messages in this thread | | | Date | Mon, 13 Jul 2015 23:15:34 +0800 | From | Xiao Guangrong <> | Subject | Re: [PATCH v3 01/10] KVM: MMU: fix decoding cache type from MTRR |
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On 07/13/2015 11:13 PM, Paolo Bonzini wrote: > On 13/07/2015 16:45, Xiao Guangrong wrote: >>> + /* MTRR is completely disabled, use UC for all of physical >>> memory. */ >>> + if (!(mtrr_state->enabled & 0x2)) >>> + return MTRR_TYPE_UNCACHABLE; >>> >>> actually disappears in commit fa61213746a7 (KVM: MTRR: simplify >>> kvm_mtrr_get_guest_memory_type, 2015-06-15). >> >> :( >> >> Based on the SDM, UC is applied to all memory rather than default-type >> if MTRR is disabled. > > There are two issues I think. One is that I cannot find in the current > code that "UC is applied to all memory rather than default-type if MTRR > is disabled". mtrr_default_type unconditionally looks at > mtrr_state->deftype.
Yes... Will fix.
> >> However, fast boot came back if "return 0xFF" here. So fast boot expects >> that the memory type is WB. > > Yes. > >>> >>> static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state) >>> { >>> if (mtrr_is_enabled(mtrr_state)) >>> return mtrr_state->deftype & >>> IA32_MTRR_DEF_TYPE_TYPE_MASK; >>> else >>> return MTRR_TYPE_UNCACHABLE; >>> } >>> >>> ? Then it's easy to add a quirk that makes the default WRITEBACK until >>> MTRRs are enabled. >> >> It is the wrong configure in OVMF... shall we need to adjust KVM to satisfy >> OVMF? > > That's what quirks are for... The firmware should still be fixed of course.
I see, will do it.
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