[PATCH v2 6/8] x86/kvm: Add KVM_FEATURE_MSI_EXT_DEST_ID
From: David Woodhouse <dwmw2@infradead.org>
Date: 2020-10-09 10:46:49
Also in:
kvm, lkml
Subsystem:
documentation, kernel virtual machine (kvm), kernel virtual machine for x86 (kvm/x86), kvm paravirt (kvm/paravirt), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Jonathan Corbet, Paolo Bonzini, Sean Christopherson, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: David Woodhouse <redacted> 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 <redacted> Acked-by: Paolo Bonzini <pbonzini@redhat.com> --- 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