From: David Woodhouse <dwmw@xxxxxxxxxxxx> This allows the host to indicate that MSI emulation supports 15-bit destination IDs, allowing up to 32768 CPUs without interrupt remapping. cf. https://patchwork.kernel.org/patch/11816693/ for qemu Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx> Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> --- Documentation/virt/kvm/cpuid.rst | 4 ++++ arch/x86/include/uapi/asm/kvm_para.h | 1 + arch/x86/kernel/kvm.c | 6 ++++++ 3 files changed, 11 insertions(+) diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst index a7dff9186bed..1726b5925d2b 100644 --- a/Documentation/virt/kvm/cpuid.rst +++ b/Documentation/virt/kvm/cpuid.rst @@ -92,6 +92,10 @@ KVM_FEATURE_ASYNC_PF_INT 14 guest checks this feature bit async pf acknowledgment msr 0x4b564d07. +KVM_FEATURE_MSI_EXT_DEST_ID 15 guest checks this feature bit + before using extended destination + ID bits in MSI address bits 11-5. + KVM_FEATURE_CLOCSOURCE_STABLE_BIT 24 host will warn if no guest-side per-cpu warps are expeced in kvmclock diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h index 812e9b4c1114..950afebfba88 100644 --- a/arch/x86/include/uapi/asm/kvm_para.h +++ b/arch/x86/include/uapi/asm/kvm_para.h @@ -32,6 +32,7 @@ #define KVM_FEATURE_POLL_CONTROL 12 #define KVM_FEATURE_PV_SCHED_YIELD 13 #define KVM_FEATURE_ASYNC_PF_INT 14 +#define KVM_FEATURE_MSI_EXT_DEST_ID 15 #define KVM_HINTS_REALTIME 0 diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 1b51b727b140..4986b4399aef 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -743,12 +743,18 @@ static void __init kvm_init_platform(void) x86_platform.apic_post_init = kvm_apic_init; } +static bool __init kvm_msi_ext_dest_id(void) +{ + return kvm_para_has_feature(KVM_FEATURE_MSI_EXT_DEST_ID); +} + const __initconst struct hypervisor_x86 x86_hyper_kvm = { .name = "KVM", .detect = kvm_detect, .type = X86_HYPER_KVM, .init.guest_late_init = kvm_guest_init, .init.x2apic_available = kvm_para_available, + .init.msi_ext_dest_id = kvm_msi_ext_dest_id, .init.init_platform = kvm_init_platform, }; -- 2.26.2
