Patch from 4.4 that may fix booting kvm with OVMF.

.SRCINFO

@@ -19,6 +19,7 @@ pkgbase = linux-vfio
 	source = change-default-console-loglevel.patch
 	source = override_for_missing_acs_capabilities.patch
 	source = i915_317.patch
+	source = kvm-x86-obey-KVM_X86_QUIRK_CD_NW_CLEARED-in-kvm_set_cr0.patch
 	sha256sums = 4a622cc84b8a3c38d39bc17195b0c064d2b46945dfde0dae18f77b120bc9f3ae
 	sha256sums = SKIP
 	sha256sums = 596958c9c4b632fdf5e0cdc677859dccac4304ad07a217c9bcb0e4fa58dbea16
@@ -27,6 +28,7 @@ pkgbase = linux-vfio
 	sha256sums = 1256b241cd477b265a3c2d64bdc19ffe3c9bbcee82ea3994c590c2c76e767d99
 	sha256sums = 975f79348119bfba8dd972a9fbfe6b38484c45bfd228f2f6d48a0c02426ba149
 	sha256sums = ff2bb84f054633c6088ad31b450b7b96b5f4ee18667dd56772dff1d8c1687854
+	sha256sums = 2d8bf50218cff86db6723f3623823a47b1c8299a2eb0589458b0a19887799f4e
 
 pkgname = linux-vfio
 	pkgdesc = The Linux kernel and modules with patches to enable GPU passthrough with KVM

PKGBUILD

@@ -20,6 +20,7 @@ source=("https://www.kernel.org/pub/linux/kernel/v4.x/${_srcname}.tar.xz"
         'change-default-console-loglevel.patch'
         'override_for_missing_acs_capabilities.patch'
         'i915_317.patch'
+        'kvm-x86-obey-KVM_X86_QUIRK_CD_NW_CLEARED-in-kvm_set_cr0.patch'
         )
 sha256sums=('4a622cc84b8a3c38d39bc17195b0c064d2b46945dfde0dae18f77b120bc9f3ae'
             'SKIP'
@@ -28,7 +29,8 @@ sha256sums=('4a622cc84b8a3c38d39bc17195b0c064d2b46945dfde0dae18f77b120bc9f3ae'
             'f0d90e756f14533ee67afda280500511a62465b4f76adcc5effa95a40045179c'
             '1256b241cd477b265a3c2d64bdc19ffe3c9bbcee82ea3994c590c2c76e767d99'
             '975f79348119bfba8dd972a9fbfe6b38484c45bfd228f2f6d48a0c02426ba149'
-            'ff2bb84f054633c6088ad31b450b7b96b5f4ee18667dd56772dff1d8c1687854')
+            'ff2bb84f054633c6088ad31b450b7b96b5f4ee18667dd56772dff1d8c1687854'
+            '2d8bf50218cff86db6723f3623823a47b1c8299a2eb0589458b0a19887799f4e')
 validpgpkeys=(
               'ABAF11C65A2970B130ABE3C479BE3E4300411886' # Linus Torvalds
               '647F28654894E3BD457199BE38DBBDC86092693E' # Greg Kroah-Hartman
@@ -64,6 +66,10 @@ prepare() {
   echo '==> Applying ACS override patch'
   patch -p1 -i "${srcdir}/override_for_missing_acs_capabilities.patch"
 
+  # Backport of 879ae1880449 from 4.4 to fix booting with OVMF
+  echo '==> Applying OVMF kvm boot patch'
+  patch -p1 -i "${srcdir}/kvm-x86-obey-KVM_X86_QUIRK_CD_NW_CLEARED-in-kvm_set_cr0.patch"
+
   if [ "${_kernelname}" != "" ]; then
     sed -i "s|CONFIG_LOCALVERSION=.*|CONFIG_LOCALVERSION=\"${_kernelname}\"|g" ./.config
     sed -i "s|CONFIG_LOCALVERSION_AUTO=.*|CONFIG_LOCALVERSION_AUTO=n|" ./.config

kvm-x86-obey-KVM_X86_QUIRK_CD_NW_CLEARED-in-kvm_set_cr0.patch

@@ -0,0 +1,53 @@
+From 879ae1880449c88db11c1ebdaedc2da79b2fe73f Mon Sep 17 00:00:00 2001
+From: Laszlo Ersek <lersek@redhat.com>
+Date: Wed, 4 Nov 2015 12:54:41 +0100
+Subject: KVM: x86: obey KVM_X86_QUIRK_CD_NW_CLEARED in kvm_set_cr0()
+
+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.
+
+Fixes: b18d5431acc7a2fd22767925f3a6f597aa4bd29e
+Cc: stable@vger.kernel.org
+Cc: Jordan Justen <jordan.l.justen@intel.com>
+Cc: Alex Williamson <alex.williamson@redhat.com>
+Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
+Tested-by: Janusz Mocek <januszmk6@gmail.com>
+Signed-off-by: Laszlo Ersek <lersek@redhat.com>#
+Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+---
+ arch/x86/kvm/x86.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
+index a24bae0..30723a4 100644
+--- a/arch/x86/kvm/x86.c
++++ b/arch/x86/kvm/x86.c
+@@ -625,7 +625,9 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
+ 	if ((cr0 ^ old_cr0) & update_bits)
+ 		kvm_mmu_reset_context(vcpu);
+ 
+-	if ((cr0 ^ old_cr0) & X86_CR0_CD)
++	if (((cr0 ^ old_cr0) & X86_CR0_CD) &&
++	    kvm_arch_has_noncoherent_dma(vcpu->kvm) &&
++	    !kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))
+ 		kvm_zap_gfn_range(vcpu->kvm, 0, ~0ULL);
+ 
+ 	return 0;
+-- 
+cgit v0.11.2
+