Messages in this thread | | | Date | Mon, 13 Jul 2015 02:59:03 +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 01:33 AM, Alex Williamson wrote: > On Wed, 2015-05-13 at 14:42 +0800, Xiao Guangrong wrote: >> There are some bugs in current get_mtrr_type(); >> 1: bit 1 of mtrr_state->enabled is corresponding bit 11 of >> IA32_MTRR_DEF_TYPE MSR which completely control MTRR's enablement >> that means other bits are ignored if it is cleared >> >> 2: the fixed MTRR ranges are controlled by bit 0 of >> mtrr_state->enabled (bit 10 of IA32_MTRR_DEF_TYPE) >> >> 3: if MTRR is disabled, UC is applied to all of physical memory rather >> than mtrr_state->def_type >> >> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> >> --- >> arch/x86/kvm/mmu.c | 14 ++++++-------- >> 1 file changed, 6 insertions(+), 8 deletions(-) > > > I'm seeing a significant regression in boot performance on Intel > hardware with assigned devices that bisects back to this patch. There's > a long delay with Seabios between the version splash and execution of > option ROMs, and a _very_ long delay with OVMF before the display is > initialized. The delay is long enough that users are reporting their > previously working VM is hung with 100% CPU usage on v4.2-rc1. Thanks, >
Alex, thanks for your report. I will try to reproduce and fix it asap.
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