From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
To: Laszlo Ersek <lersek@redhat.com>, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Jordan Justen <jordan.l.justen@intel.com>,
Janusz Mocek <januszmk6@gmail.com>,
Alex Williamson <alex.williamson@redhat.com>
Subject: Re: [PATCH] KVM: x86: obey KVM_X86_QUIRK_CD_NW_CLEARED in kvm_set_cr0()
Date: Wed, 4 Nov 2015 11:09:06 +0800 [thread overview]
Message-ID: <563976D2.6080909@linux.intel.com> (raw)
In-Reply-To: <1446575660-16560-1-git-send-email-lersek@redhat.com>
On 11/04/2015 02:34 AM, Laszlo Ersek wrote:
> Commit b18d5431acc7 ("KVM: x86: fix CR0.CD virtualization") was
> technically correct, but it broke OVMF guests by slowing down various
> parts of the firmware.
>
> Commit fb279950ba02 ("KVM: vmx: obey KVM_QUIRK_CD_NW_CLEARED") quirked the
> first function modified by b18d5431acc7, vmx_get_mt_mask(), for OVMF's
> sake. This restored the speed of the OVMF code that runs before
> PlatformPei (including the memory intensive LZMA decompression in SEC).
>
> This patch extends the quirk to the second function modified by
> b18d5431acc7, kvm_set_cr0(). It eliminates the intrusive slowdown that
> hits the EFI_MP_SERVICES_PROTOCOL implementation of edk2's
> UefiCpuPkg/CpuDxe -- which is built into OVMF --, when CpuDxe starts up
> all APs at once for initialization, in order to count them.
>
> We also carry over the kvm_arch_has_noncoherent_dma() sub-condition from
> the other half of the original commit b18d5431acc7.
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
next prev parent reply other threads:[~2015-11-04 3:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-03 18:34 [PATCH] KVM: x86: obey KVM_X86_QUIRK_CD_NW_CLEARED in kvm_set_cr0() Laszlo Ersek
2015-11-03 18:57 ` Laszlo Ersek
2015-11-03 23:57 ` Janusz Mocek
2015-11-04 3:09 ` Xiao Guangrong [this message]
2015-11-04 11:56 ` Paolo Bonzini
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