Hi,
Would you mind rewording the commit subject to:
x86: Set the correct APIC ID
On Wed, Feb 16, 2022 at 12:38:34PM +0800, Muchun Song wrote:
> When I boot kernel, the dmesg will print the following message:
^^^^^^^^^^^^^^^^^^
Would you mind replacing that with "When kvmtool boots a kernel, [..]"?
>
> [Firmware Bug]: CPU1: APIC id mismatch. Firmware: 1 APIC: 30
>
> Fix this by setting up correct initial_apicid to cpu_id.
Thank you for fixing this. I've always wanted to fix that error, but I didn't
know enough about the x86 architecture.
>
> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> ---
> x86/cpuid.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/x86/cpuid.c b/x86/cpuid.c
> index c3b67d9..aa213d5 100644
> --- a/x86/cpuid.c
> +++ b/x86/cpuid.c
> @@ -8,7 +8,7 @@
>
> #define MAX_KVM_CPUID_ENTRIES 100
>
> -static void filter_cpuid(struct kvm_cpuid2 *kvm_cpuid)
> +static void filter_cpuid(struct kvm_cpuid2 *kvm_cpuid, int cpu_id)
> {
> unsigned int signature[3];
> unsigned int i;
> @@ -28,6 +28,8 @@ static void filter_cpuid(struct kvm_cpuid2 *kvm_cpuid)
> entry->edx = signature[2];
> break;
> case 1:
> + entry->ebx &= ~(0xff << 24);
> + entry->ebx |= cpu_id << 24;
> /* Set X86_FEATURE_HYPERVISOR */
> if (entry->index == 0)
> entry->ecx |= (1 << 31);
> @@ -80,7 +82,7 @@ void kvm_cpu__setup_cpuid(struct kvm_cpu *vcpu)
> if (ioctl(vcpu->kvm->sys_fd, KVM_GET_SUPPORTED_CPUID, kvm_cpuid) < 0)
> die_perror("KVM_GET_SUPPORTED_CPUID failed");
>
> - filter_cpuid(kvm_cpuid);
> + filter_cpuid(kvm_cpuid, vcpu->cpu_id);
Tested it and it works:
Tested-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Thanks,
Alex
>
> if (ioctl(vcpu->vcpu_fd, KVM_SET_CPUID2, kvm_cpuid) < 0)
> die_perror("KVM_SET_CPUID2 failed");
> --
> 2.11.0
>
