Thanks for your explanations - I thought so too. The new Intel microcode is applied, as you can see: dmesg | grep microcode [ 0.000000] microcode: microcode updated early to revision 0x714, date = 2018-05-08 [ 2.810683] microcode: sig=0x206d7, pf=0x4, revision=0x714 [ 2.813340] microcode: Microcode Update Driver: v2.2.
The host kernel has the features you listed: cat /proc/cpuinfo | grep flags flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm epb pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid xsaveopt dtherm ida arat pln pts flush_l1d I'm still looking for a way to display the CPU flags under Windows. Here is my systeminfo (Windows) output: systeminfo Host Name: DESKTOP-K3DEAH0 OS Name: Microsoft Windows 10 Pro OS Version: 10.0.17134 N/A Build 17134 OS Manufacturer: Microsoft Corporation OS Configuration: Standalone Workstation OS Build Type: Multiprocessor Free Registered Owner: win Registered Organization: Product ID: 00330-80000-00000-AA554 Original Install Date: 05-Jun-18, 22:58:49 System Boot Time: 25-Aug-18, 00:17:19 System Manufacturer: QEMU System Model: Standard PC (Q35 + ICH9, 2009) System Type: x64-based PC Processor(s): 1 Processor(s) Installed. [01]: Intel64 Family 6 Model 45 Stepping 7 GenuineIntel ~3200 Mhz BIOS Version: EFI Development Kit II / OVMF 0.0.0, 06-Feb-15 Windows Directory: C:\WINDOWS System Directory: C:\WINDOWS\system32 Boot Device: \Device\HarddiskVolume2 System Locale: en-us;English (United States) Input Locale: en-us;English (United States) Time Zone: (UTC+02:00) Jerusalem Total Physical Memory: 16,380 MB Available Physical Memory: 12,955 MB Virtual Memory: Max Size: 17,380 MB Virtual Memory: Available: 13,233 MB Virtual Memory: In Use: 4,147 MB Page File Location(s): C:\pagefile.sys Domain: WORKGROUP Logon Server: \\DESKTOP-K3DEAH0 Hotfix(s): 4 Hotfix(s) Installed. [01]: KB4338832 [02]: KB4343669 [03]: KB4343902 [04]: KB4343909 Network Card(s): 1 NIC(s) Installed. [01]: Red Hat VirtIO Ethernet Adapter Connection Name: Ethernet 6 DHCP Enabled: No IP address(es) [01]: 192.168.0.200 Hyper-V Requirements: A hypervisor has been detected. Features required for Hyper-V will not be displayed. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1788665 Title: Low 2D graphics performance with Windows 10 (1803) VGA passthrough VM using "Spectre" protection Status in QEMU: New Bug description: Windows 10 (1803) VM using VGA passthrough via qemu script. After upgrading Windows 10 Pro VM to version 1803, or possibly after applying the March/April security updates from Microsoft, the VM would show low 2D graphics performance (sluggishness in 2D applications and low Passmark results). Turning off Spectre vulnerability protection in Windows remedies the issue. Expected behavior: qemu/kvm hypervisor to expose firmware capabilities of host to guest OS - see https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/CVE-2017-5715-and-hyper-v-vms Background: Starting in March or April Microsoft began to push driver updates in their updates / security updates. See https://support.microsoft.com /en-us/help/4073757/protect-your-windows-devices-against-spectre- meltdown One update concerns the Intel microcode - see https://support.microsoft.com/en-us/help/4100347. It is activated by default within Windows. Once the updates are applied within the Windows guest, 2D graphics performance drops significantly. Other performance benchmarks are not affected. A bare metal Windows installation does not display a performance loss after the update. See https://heiko-sieger.info/low-2d-graphics- benchmark-with-windows-10-1803-kvm-vm/ Similar reports can be found here: https://www.reddit.com/r/VFIO/comments/97unx4/passmark_lousy_2d_graphics_performance_on_windows/ Hardware: 6 core Intel Core i7-3930K (-MT-MCP-) Host OS: Linux Mint 19/Ubuntu 18.04 Kernel: 4.15.0-32-generic x86_64 Qemu: QEMU emulator version 2.11.1 Intel microcode (host): 0x714 dmesg | grep microcode [ 0.000000] microcode: microcode updated early to revision 0x714, date = 2018-05-08 [ 2.810683] microcode: sig=0x206d7, pf=0x4, revision=0x714 [ 2.813340] microcode: Microcode Update Driver: v2.2. Note: I manually updated the Intel microcode on the host from 0x713 to 0x714. However, both microcode versions produce the same result in the Windows guest. Guest OS: Windows 10 Pro 64 bit, release 1803 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1788665/+subscriptions