commit bd4b5f3b1a308a1fab69ede5579d20353ea17b06
author Slava Malyugin <slavamn@google.com> Tue Feb 07 20:43:03 2017
committer chrome-bot <chrome-bot@chromium.org> Thu Feb 09 22:58:27 2017
tree dfcf7a6c89d6bc6c1dc94c12c29217c0bc6d10e4
parent 9c96986c6ed7d48108d0fe2e464e5565aa18f704

Change ports hyperthreading reporting to kvmtool from qemu

It improves speed of kernel compile from 8min to 6min:30sec.

Change-Id: I917d7aa1de29f55b4494639bbefaba7a73b517cc
BUG=None
TEST=kernel compile in VM on hyperthreaded x86 notebook
Reviewed-on: https://chromium-review.googlesource.com/439386
Commit-Ready: Slava Malyugin <slavamn@chromium.org>
Tested-by: Slava Malyugin <slavamn@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>

x86/cpuid.c

diff --git a/x86/cpuid.c b/x86/cpuid.c
index c3b67d9..d9f4fc3 100644
--- a/x86/cpuid.c
+++ b/x86/cpuid.c
@@ -8,7 +8,7 @@
 
 #define	MAX_KVM_CPUID_ENTRIES		100
 
-static void filter_cpuid(struct kvm_cpuid2 *kvm_cpuid)
+static void filter_cpuid(struct kvm_cpu *vcpu, struct kvm_cpuid2 *kvm_cpuid)
 {
 	unsigned int signature[3];
 	unsigned int i;
@@ -31,6 +31,11 @@
 			/* Set X86_FEATURE_HYPERVISOR */
 			if (entry->index == 0)
 				entry->ecx |= (1 << 31);
+			entry->ebx = (vcpu->cpu_id << 24) | (8 << 8);
+			if (vcpu->kvm->nrcpus > 1) {
+				entry->ebx |= vcpu->kvm->nrcpus << 16;
+				entry->edx |= (1 << 28);
+			}
 			break;
 		case 6:
 			/* Clear X86_FEATURE_EPB */
@@ -80,7 +85,7 @@
 	if (ioctl(vcpu->kvm->sys_fd, KVM_GET_SUPPORTED_CPUID, kvm_cpuid) < 0)
 		die_perror("KVM_GET_SUPPORTED_CPUID failed");
 
-	filter_cpuid(kvm_cpuid);
+	filter_cpuid(vcpu, kvm_cpuid);
 
 	if (ioctl(vcpu->vcpu_fd, KVM_SET_CPUID2, kvm_cpuid) < 0)
 		die_perror("KVM_SET_CPUID2 failed");