https://bugzilla.kernel.org/show_bug.cgi?id=216045 Bug ID: 216045 Summary: KVM x2APIC virtualization causes EOI to be ignored Product: Virtualization Version: unspecified Kernel Version: 5.17.9 Hardware: Intel OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: kvm Assignee: virtualization_kvm@xxxxxxxxxxxxxxxxxxxx Reporter: ercli@xxxxxxxxxxx Regression: No Created attachment 301071 --> https://bugzilla.kernel.org/attachment.cgi?id=301071&action=edit Guest hypervisor to reproduce this bug (xz compressed) CPU model: 11th Gen Intel(R) Core(TM) i7-1185G7 @ 3.00GHz Host kernel version: 5.17.9 Host kernel arch: x86_64 Guest: a micro-hypervisor (called XMHF), which runs Linux (64-bit Debian, 5.10.0-9-amd64) QEMU command line: qemu-system-x86_64 -m 512M -smp 2 -cpu Haswell,vmx=yes -enable-kvm -serial stdio -drive media=disk,file=c.img,index=1 -drive media=disk,file=debian11x64.qcow2,index=2 The problem goes away if using -machine kernel_irqchip=off This problem cannot be tested with -accel tcg , because the guest requires nested virtualization Files used to reproduce this bug: debian11x64.qcow2 (3.3G) is uploaded at https://drive.google.com/uc?id=1LtUwnzH8pDvjoBhJhxk5wIz9_UTlGaBA . It should be equivalent to a freshly installed Debian 5.10.0-9-amd64 on QEMU. Its kaslr is disabled for debugging convenience. c.img (8M) is uploaded at https://drive.google.com/uc?id=1g3c9KMAoh_Yvb9bzSuOBMG5L-2VX6twU . It is also compressed as c.img.xz and uploaded with this bug. It is built from https://github.com/lxylxy123456/uberxmhf/tree/ab7968ed8017f43978081862526636f75c80a3b7 . Actual behavior: After running the QEMU command above, the hypervisor (XMHF) will boot and then chain load Debian as a guest OS. Debian starts to boot and stuck. In QEMU's monitor, if I enter "info lapic", I see ... ISR 253 IRR 48 236 253 Expected behavior: When running the QEMU command above, the hypervisor should boot Debian, and Debian should boot successfully. The VGA screen should show "debian login:". The expected behavior can be achieved in a few ways: 1. Remove "-drive media=disk,file=c.img,index=1" from QEMU command line. This will boot Debian directly (instead of booting XMHF and then boot Debian) 2. Add "-machine kernel_irqchip=off" to the QEMU command line 3. Apply the following patch to KVM and re-compile. This patch will let KVM think that x2APIC virtualization is not available. diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h index 3f430e218..29b412ae4 100644 --- a/arch/x86/kvm/vmx/capabilities.h +++ b/arch/x86/kvm/vmx/capabilities.h @@ -157,8 +157,7 @@ static inline bool cpu_has_vmx_rdtscp(void) static inline bool cpu_has_vmx_virtualize_x2apic_mode(void) { - return vmcs_config.cpu_based_2nd_exec_ctrl & - SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE; + return 0; } static inline bool cpu_has_vmx_vpid(void) -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
