From cc2dd4027a43bb36c846f195a764edabc0828602 Mon Sep 17 00:00:00 2001
From: "Denis V. Lunev" <den@openvz.org>
Date: Sat, 1 Aug 2015 16:08:20 -0700
Subject: [PATCH] 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>
---
arch/x86/include/asm/mshyperv.h | 1 +
arch/x86/kernel/cpu/mshyperv.c | 1 +
drivers/hv/vmbus_drv.c | 4 ++--
3 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index d02f9c9a6592..aaf59b7da98a 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -7,6 +7,7 @@
struct ms_hyperv_info {
u32 features;
+ u32 misc_features;
u32 hints;
};
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 5ea5bbcc85b3..f794bfa3c138 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -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",
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index b6114cc89aeb..e7b0bcd453e7 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -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);