Re: qemu-4.2: failed to set MSR 0x48b to 0x1582e00000000: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed.

[Paolo Bonzini <pbonzini@redhat.com>]

On 14/12/19 02:31, Philippe Mathieu-Daudé wrote:
> 
> failed to launch qemu: exit status 1, error messages from qemu log:
> qemu-system-x86_64: error: failed to set MSR 0x48b to 0x1582e00000000
> qemu-system-x86_64: /root/qemu/target/i386/kvm.c:2947: kvm_put_msrs:
> Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed.

It could be a KVM bug too.  The following features are being enabled:

#define VMX_SECONDARY_EXEC_XSAVES                   0x00100000
#define VMX_SECONDARY_EXEC_SHADOW_VMCS              0x00004000
#define VMX_SECONDARY_EXEC_ENABLE_INVPCID           0x00001000
#define VMX_SECONDARY_EXEC_RDRAND_EXITING           0x00000800
#define VMX_SECONDARY_EXEC_ENABLE_VPID              0x00000020
#define VMX_SECONDARY_EXEC_ENABLE_EPT               0x00000002
#define VMX_SECONDARY_EXEC_DESC                     0x00000004
#define VMX_SECONDARY_EXEC_RDTSCP                   0x00000008

Can you try:

1) running "vmxcap" on the Azure VM

2) adding "-vmx-xsaves,-vmx-shadow-vmcs" to the "-cpu" option and, if it
works, add only one of the two.

3) if it doesn't work, adding "-vmx" to the "-cpu" option.  Either way,
run "x86info -a" in the resulting VM.

Thanks,

Paolo