diff options
| author | Colin Percival <cperciva@FreeBSD.org> | 2026-02-22 04:09:01 +0000 |
|---|---|---|
| committer | Colin Percival <cperciva@FreeBSD.org> | 2026-03-28 05:54:59 +0000 |
| commit | 7b6be0014a4eb81943491122bae70914b7fd82b6 (patch) | |
| tree | dd1d6998bbd2525195730a760dc5ea1720417bdf | |
| parent | 8dd9a0d52175fbc5dafed851fb95a289a94fb6cd (diff) | |
Hyper-V: Detect Extended Destination ID support
Hyper-V advertises support for the Extended Destination ID standard via
bit 2 of the value returned in the EAX register when the hypervisor
stack properties are queried via CPUID.
This is based on a commit to the Linux kernel, as there does not seem
to be any other documentation of this feature.
Reviewed by: Souradeep Chakrabarti
MFC after: 3 weeks
Sponsored by: Amazon
Differential Revision: https://reviews.freebsd.org/D55432
| -rw-r--r-- | sys/dev/hyperv/vmbus/x86/hyperv_reg.h | 6 | ||||
| -rw-r--r-- | sys/x86/x86/local_apic.c | 9 |
2 files changed, 15 insertions, 0 deletions
diff --git a/sys/dev/hyperv/vmbus/x86/hyperv_reg.h b/sys/dev/hyperv/vmbus/x86/hyperv_reg.h index 0597a1fea953..e7560d00f25e 100644 --- a/sys/dev/hyperv/vmbus/x86/hyperv_reg.h +++ b/sys/dev/hyperv/vmbus/x86/hyperv_reg.h @@ -45,4 +45,10 @@ #define CPUID_LEAF_HV_IDENTITY 0x40000002 #define CPUID_LEAF_HV_FEATURES 0x40000003 #define CPUID_LEAF_HV_RECOMMENDS 0x40000004 + +#define CPUID_LEAF_HV_STACK_INTERFACE 0x40000081 +#define HYPERV_STACK_INTERFACE_EAX_SIG 0x31235356 /* "VS#1" */ +#define CPUID_LEAF_HV_STACK_PROPERTIES 0x40000082 +#define HYPERV_PROPERTIES_EXT_DEST_ID 0x00000004 + #endif /* !_HYPERV_REG_H_ */ diff --git a/sys/x86/x86/local_apic.c b/sys/x86/x86/local_apic.c index 20f095a13574..cd5e4d474080 100644 --- a/sys/x86/x86/local_apic.c +++ b/sys/x86/x86/local_apic.c @@ -75,6 +75,7 @@ #include <x86/kvm.h> #include <contrib/xen/arch-x86/cpuid.h> #include <x86/bhyve.h> +#include <dev/hyperv/vmbus/x86/hyperv_reg.h> #ifdef DDB #include <sys/interrupt.h> @@ -2107,6 +2108,14 @@ detect_extended_dest_id(void) if (regs[0] & XEN_HVM_CPUID_EXT_DEST_ID) apic_ext_dest_id = 1; break; + case VM_GUEST_HV: + cpuid_count(CPUID_LEAF_HV_STACK_INTERFACE, 0, regs); + if (regs[0] != HYPERV_STACK_INTERFACE_EAX_SIG) + break; + cpuid_count(CPUID_LEAF_HV_STACK_PROPERTIES, 0, regs); + if (regs[0] & HYPERV_PROPERTIES_EXT_DEST_ID) + apic_ext_dest_id = 1; + break; case VM_GUEST_KVM: kvm_cpuid_get_features(regs); if (regs[0] & KVM_FEATURE_MSI_EXT_DEST_ID) |