Install the Hyper-V specific interrupt handler only when needed. This would
permit us to get rid of the Xen check. Note that when the vmbus drivers invokes
the call to register its handler, we are sure to be running on Hyper-V.
Signed-off-by: K. Y. Srinivasan <[email protected]>
---
arch/x86/kernel/cpu/mshyperv.c | 18 +++++-------------
1 files changed, 5 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index a7d26d8..8f4be53 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -35,13 +35,6 @@ static bool __init ms_hyperv_platform(void)
if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
return false;
- /*
- * Xen emulates Hyper-V to support enlightened Windows.
- * Check to see first if we are on a Xen Hypervisor.
- */
- if (xen_cpuid_base())
- return false;
-
cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
&eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
@@ -82,12 +75,6 @@ static void __init ms_hyperv_init_platform(void)
if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
-#if IS_ENABLED(CONFIG_HYPERV)
- /*
- * Setup the IDT for hypervisor callback.
- */
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
-#endif
}
const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
@@ -103,6 +90,11 @@ static irq_handler_t vmbus_isr;
void hv_register_vmbus_handler(int irq, irq_handler_t handler)
{
+ /*
+ * Setup the IDT for hypervisor callback.
+ */
+ alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
+
vmbus_irq = irq;
vmbus_isr = handler;
}
--
1.7.4.1
On Thu, Apr 18, 2013 at 08:44:46AM -0700, K. Y. Srinivasan wrote:
> Install the Hyper-V specific interrupt handler only when needed. This would
> permit us to get rid of the Xen check. Note that when the vmbus drivers invokes
> the call to register its handler, we are sure to be running on Hyper-V.
>
> Signed-off-by: K. Y. Srinivasan <[email protected]>
Looks good to me, this will address the concern. FWIW
Acked-by: Michael S. Tsirkin <[email protected]>
Any chance we can fast-path this patch into 3.9 so that we don't release
a kernel with hyper-v on Xen completely disabled?
> ---
> arch/x86/kernel/cpu/mshyperv.c | 18 +++++-------------
> 1 files changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index a7d26d8..8f4be53 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -35,13 +35,6 @@ static bool __init ms_hyperv_platform(void)
> if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
> return false;
>
> - /*
> - * Xen emulates Hyper-V to support enlightened Windows.
> - * Check to see first if we are on a Xen Hypervisor.
> - */
> - if (xen_cpuid_base())
> - return false;
> -
> cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
> &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
>
> @@ -82,12 +75,6 @@ static void __init ms_hyperv_init_platform(void)
>
> if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
> clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
> -#if IS_ENABLED(CONFIG_HYPERV)
> - /*
> - * Setup the IDT for hypervisor callback.
> - */
> - alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
> -#endif
> }
>
> const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
> @@ -103,6 +90,11 @@ static irq_handler_t vmbus_isr;
>
> void hv_register_vmbus_handler(int irq, irq_handler_t handler)
> {
> + /*
> + * Setup the IDT for hypervisor callback.
> + */
> + alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
> +
> vmbus_irq = irq;
> vmbus_isr = handler;
> }
> --
> 1.7.4.1
Commit-ID: 7eff7ded02d1b15ba8321664839b353fa6c0c1e4
Gitweb: http://git.kernel.org/tip/7eff7ded02d1b15ba8321664839b353fa6c0c1e4
Author: K. Y. Srinivasan <[email protected]>
AuthorDate: Thu, 18 Apr 2013 08:44:46 -0700
Committer: H. Peter Anvin <[email protected]>
CommitDate: Thu, 18 Apr 2013 08:59:20 -0700
x86, hyperv: Handle Xen emulation of Hyper-V more gracefully
Install the Hyper-V specific interrupt handler only when needed. This would
permit us to get rid of the Xen check. Note that when the vmbus drivers invokes
the call to register its handler, we are sure to be running on Hyper-V.
Signed-off-by: K. Y. Srinivasan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Acked-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>
---
arch/x86/kernel/cpu/mshyperv.c | 18 +++++-------------
1 file changed, 5 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index a7d26d8..8f4be53 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -35,13 +35,6 @@ static bool __init ms_hyperv_platform(void)
if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
return false;
- /*
- * Xen emulates Hyper-V to support enlightened Windows.
- * Check to see first if we are on a Xen Hypervisor.
- */
- if (xen_cpuid_base())
- return false;
-
cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
&eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
@@ -82,12 +75,6 @@ static void __init ms_hyperv_init_platform(void)
if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
-#if IS_ENABLED(CONFIG_HYPERV)
- /*
- * Setup the IDT for hypervisor callback.
- */
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
-#endif
}
const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
@@ -103,6 +90,11 @@ static irq_handler_t vmbus_isr;
void hv_register_vmbus_handler(int irq, irq_handler_t handler)
{
+ /*
+ * Setup the IDT for hypervisor callback.
+ */
+ alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
+
vmbus_irq = irq;
vmbus_isr = handler;
}