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Commit cc2dd402 authored Aug 01, 2015 by Denis V. Lunev Committed by Greg Kroah-Hartman Aug 04, 2015

mshyperv: fix recognition of Hyper-V guest crash MSR's



Hypervisor Top Level Functional Specification v3.1/4.0 notes that cpuid
(0x40000003) EDX's 10th bit should be used to check that Hyper-V guest
crash MSR's functionality available.

This patch should fix this recognition. Currently the code checks EAX
register instead of EDX.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 4a54243f

arch/x86/include/asm/mshyperv.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -7,6 +7,7 @@

		struct ms_hyperv_info {
		u32 features;
		u32 misc_features;
		u32 hints;
		};

arch/x86/kernel/cpu/mshyperv.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -158,6 +158,7 @@ static void __init ms_hyperv_init_platform(void)
		* Extract the features and hints
		*/
		ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
		ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
		ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);

		printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",

drivers/hv/vmbus_drv.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -871,7 +871,7 @@ static int vmbus_bus_init(int irq)
		/*
		* Only register if the crash MSRs are available
		*/
		if (ms_hyperv.features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
		if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
		register_die_notifier(&hyperv_die_block);
		atomic_notifier_chain_register(&panic_notifier_list,
		&hyperv_panic_block);
		@@ -1169,7 +1169,7 @@ static void __exit vmbus_exit(void)
		hv_remove_vmbus_irq();
		tasklet_kill(&msg_dpc);
		vmbus_free_channels();
		if (ms_hyperv.features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
		if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
		unregister_die_notifier(&hyperv_die_block);
		atomic_notifier_chain_unregister(&panic_notifier_list,
		&hyperv_panic_block);