From: David Woodhouse <dwmw@xxxxxxxxxxxx>
This allows the host to indicate that IOAPIC and MSI emulation supports
15-bit destination IDs, allowing up to 32Ki CPUs without remapping.
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
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
