2015-07-02 10:17:53

by Denis V. Lunev

Subject: [RFC PATCH 1/1] mshyperv: fix recognition of Hyper-V guest crash MSR's

From: Andrey Smetanin <[email protected]>

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 <[email protected]>
Signed-off-by: Denis V. Lunev <[email protected]>
CC: Nick Meier <[email protected]>
CC: K. Y. Srinivasan <[email protected]>
CC: Haiyang Zhang <[email protected]>
---
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 c163215..eebe433 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 aad4bd8..6d172a2 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -114,6 +114,7 @@ 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 cf20400..67af13a 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -841,7 +841,7 @@ 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) {
atomic_notifier_chain_register(&panic_notifier_list,
&hyperv_panic_block);
}
@@ -1110,7 +1110,7 @@ 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) {
atomic_notifier_chain_unregister(&panic_notifier_list,
&hyperv_panic_block);
}
--
2.1.4

2015-07-02 11:23:04

by Vitaly Kuznetsov

Subject: Re: [RFC PATCH 1/1] mshyperv: fix recognition of Hyper-V guest crash MSR's

"Denis V. Lunev" <[email protected]> writes:

> From: Andrey Smetanin <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Denis V. Lunev <[email protected]>
> CC: Nick Meier <[email protected]>
> CC: K. Y. Srinivasan <[email protected]>
> CC: Haiyang Zhang <[email protected]>

Something went wrong and I don't see K.Y. on the CC: list of your
email. Fixed now.

> ---
> 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 c163215..eebe433 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 aad4bd8..6d172a2 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -114,6 +114,7 @@ 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 cf20400..67af13a 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -841,7 +841,7 @@ 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) {
> atomic_notifier_chain_register(&panic_notifier_list,
> &hyperv_panic_block);
> }
> @@ -1110,7 +1110,7 @@ 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) {
> atomic_notifier_chain_unregister(&panic_notifier_list,
> &hyperv_panic_block);
> }

--
Vitaly