Date: Sat, 28 Mar 2026 05:56:37 +0000 From: Colin Percival <cperciva@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 7b6be0014a4e - main - Hyper-V: Detect Extended Destination ID support Message-ID: <69c76d95.4100b.d90ba62@gitrepo.freebsd.org>
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The branch main has been updated by cperciva: URL: https://cgit.FreeBSD.org/src/commit/?id=7b6be0014a4eb81943491122bae70914b7fd82b6 commit 7b6be0014a4eb81943491122bae70914b7fd82b6 Author: Colin Percival <cperciva@FreeBSD.org> AuthorDate: 2026-02-22 04:09:01 +0000 Commit: Colin Percival <cperciva@FreeBSD.org> CommitDate: 2026-03-28 05:54:59 +0000 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 --- sys/dev/hyperv/vmbus/x86/hyperv_reg.h | 6 ++++++ sys/x86/x86/local_apic.c | 9 +++++++++ 2 files changed, 15 insertions(+) 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)home | help
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