[PATCH 1/2] apic: Move hypervisor detection of x2apic to hypervisor.h

[PATCH 1/2] apic: Move hypervisor detection of x2apic to hypervisor.h

[Sheng Yang]

Xen can use it later.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
 arch/x86/include/asm/hypervisor.h |    9 +++++++++
 arch/x86/kernel/apic/apic.c       |    5 +++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index ff2546c..0c6f7af 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -20,6 +20,8 @@
 #ifndef _ASM_X86_HYPERVISOR_H
 #define _ASM_X86_HYPERVISOR_H
 
+#include <asm/kvm_para.h>
+
 extern void init_hypervisor(struct cpuinfo_x86 *c);
 extern void init_hypervisor_platform(void);
 
@@ -47,4 +49,11 @@ extern const struct hypervisor_x86 x86_hyper_vmware;
 extern const struct hypervisor_x86 x86_hyper_ms_hyperv;
 extern const struct hypervisor_x86 x86_hyper_xen_hvm;
 
+static inline bool hypervisor_x2apic_available(void)
+{
+	if (kvm_para_available())
+		return true;
+	return false;
+}
+
 #endif
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 3f838d5..8408f2d 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -50,8 +50,8 @@
 #include <asm/mtrr.h>
 #include <asm/smp.h>
 #include <asm/mce.h>
-#include <asm/kvm_para.h>
 #include <asm/tsc.h>
+#include <asm/hypervisor.h>
 
 unsigned int num_processors;
 
@@ -1476,7 +1476,8 @@ void __init enable_IR_x2apic(void)
 		/* IR is required if there is APIC ID > 255 even when running
 		 * under KVM
 		 */
-		if (max_physical_apicid > 255 || !kvm_para_available())
+		if (max_physical_apicid > 255 ||
+		    !hypervisor_x2apic_available())
 			goto nox2apic;
 		/*
 		 * without IR all CPUs can be addressed by IOAPIC/MSI
-- 
1.7.0.1

[PATCH 2/2] xen: HVM X2APIC support

[Sheng Yang]

This patch is similiar to Gleb Natapov's patch for KVM, which enable the
hypervisor to emulate x2apic feature for the guest. By this way, the emulation
of lapic would be simpler with x2apic interface(MSR), and faster.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
 arch/x86/include/asm/hypervisor.h     |    3 ++
 arch/x86/include/asm/xen/hypervisor.h |   35 +++++++++++++++++++++++++++++++++
 arch/x86/xen/enlighten.c              |   30 ++++++++++-----------------
 3 files changed, 49 insertions(+), 19 deletions(-)

diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index 0c6f7af..7a15153 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -21,6 +21,7 @@
 #define _ASM_X86_HYPERVISOR_H
 
 #include <asm/kvm_para.h>
+#include <asm/xen/hypervisor.h>
 
 extern void init_hypervisor(struct cpuinfo_x86 *c);
 extern void init_hypervisor_platform(void);
@@ -53,6 +54,8 @@ static inline bool hypervisor_x2apic_available(void)
 {
 	if (kvm_para_available())
 		return true;
+	if (xen_x2apic_para_available())
+		return true;
 	return false;
 }
 
diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h
index 396ff4c..66d0fff 100644
--- a/arch/x86/include/asm/xen/hypervisor.h
+++ b/arch/x86/include/asm/xen/hypervisor.h
@@ -37,4 +37,39 @@
 extern struct shared_info *HYPERVISOR_shared_info;
 extern struct start_info *xen_start_info;
 
+#include <asm/processor.h>
+
+static inline uint32_t xen_cpuid_base(void)
+{
+	uint32_t base, eax, ebx, ecx, edx;
+	char signature[13];
+
+	for (base = 0x40000000; base < 0x40010000; base += 0x100) {
+		cpuid(base, &eax, &ebx, &ecx, &edx);
+		*(uint32_t *)(signature + 0) = ebx;
+		*(uint32_t *)(signature + 4) = ecx;
+		*(uint32_t *)(signature + 8) = edx;
+		signature[12] = 0;
+
+		if (!strcmp("XenVMMXenVMM", signature) && ((eax - base) >= 2))
+			return base;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_XEN
+extern bool xen_hvm_need_lapic(void);
+
+static inline bool xen_x2apic_para_available(void)
+{
+	return xen_hvm_need_lapic();
+}
+#else
+static inline bool xen_x2apic_para_available(void)
+{
+	return (xen_cpuid_base() != 0);
+}
+#endif
+
 #endif /* _ASM_X86_XEN_HYPERVISOR_H */
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 44dcad4..3784bab 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1256,25 +1256,6 @@ asmlinkage void __init xen_start_kernel(void)
 #endif
 }
 
-static uint32_t xen_cpuid_base(void)
-{
-	uint32_t base, eax, ebx, ecx, edx;
-	char signature[13];
-
-	for (base = 0x40000000; base < 0x40010000; base += 0x100) {
-		cpuid(base, &eax, &ebx, &ecx, &edx);
-		*(uint32_t *)(signature + 0) = ebx;
-		*(uint32_t *)(signature + 4) = ecx;
-		*(uint32_t *)(signature + 8) = edx;
-		signature[12] = 0;
-
-		if (!strcmp("XenVMMXenVMM", signature) && ((eax - base) >= 2))
-			return base;
-	}
-
-	return 0;
-}
-
 static int init_hvm_pv_info(int *major, int *minor)
 {
 	uint32_t eax, ebx, ecx, edx, pages, msr, base;
@@ -1384,6 +1365,17 @@ static bool __init xen_hvm_platform(void)
 	return true;
 }
 
+bool xen_hvm_need_lapic(void)
+{
+	if (xen_pv_domain())
+		return false;
+	if (xen_hvm_domain() &&
+	   (xen_feature(XENFEAT_hvm_pirqs) || xen_have_vector_callback))
+		return false;
+	return (xen_cpuid_base() != 0);
+}
+EXPORT_SYMBOL_GPL(xen_hvm_need_lapic);
+
 const __refconst struct hypervisor_x86 x86_hyper_xen_hvm = {
 	.name			= "Xen HVM",
 	.detect			= xen_hvm_platform,
-- 
1.7.0.1

Re: [PATCH 2/2] xen: HVM X2APIC support

[Stefano Stabellini]

On Tue, 7 Dec 2010, Sheng Yang wrote:
> +bool xen_hvm_need_lapic(void)
> +{
> +	if (xen_pv_domain())
> +		return false;
> +	if (xen_hvm_domain() &&
> +	   (xen_feature(XENFEAT_hvm_pirqs) || xen_have_vector_callback))
> +		return false;
> +	return (xen_cpuid_base() != 0);
> +}
> +EXPORT_SYMBOL_GPL(xen_hvm_need_lapic);
> +

Why do you want to disable x2apic
if (xen_have_vector_callback && !xen_feature(XENFEAT_hvm_pirqs))?
In this case some emulated devices are still used, like the serial, and
need interrupt delivery using an apic. Same is true for all the
pci devices assigned to the VM.
The only case in which the apic is basically left unused is
(xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback).

[PATCH 1/2] apic: Move hypervisor detection of x2apic to hypervisor.h

[Sheng Yang]

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
 arch/x86/include/asm/hypervisor.h |    9 +++++++++
 arch/x86/kernel/apic/apic.c       |    5 +++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index ff2546c..0c6f7af 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -20,6 +20,8 @@
 #ifndef _ASM_X86_HYPERVISOR_H
 #define _ASM_X86_HYPERVISOR_H
 
+#include <asm/kvm_para.h>
+
 extern void init_hypervisor(struct cpuinfo_x86 *c);
 extern void init_hypervisor_platform(void);
 
@@ -47,4 +49,11 @@ extern const struct hypervisor_x86 x86_hyper_vmware;
 extern const struct hypervisor_x86 x86_hyper_ms_hyperv;
 extern const struct hypervisor_x86 x86_hyper_xen_hvm;
 
+static inline bool hypervisor_x2apic_available(void)
+{
+	if (kvm_para_available())
+		return true;
+	return false;
+}
+
 #endif
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 3f838d5..8408f2d 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -50,8 +50,8 @@
 #include <asm/mtrr.h>
 #include <asm/smp.h>
 #include <asm/mce.h>
-#include <asm/kvm_para.h>
 #include <asm/tsc.h>
+#include <asm/hypervisor.h>
 
 unsigned int num_processors;
 
@@ -1476,7 +1476,8 @@ void __init enable_IR_x2apic(void)
 		/* IR is required if there is APIC ID > 255 even when running
 		 * under KVM
 		 */
-		if (max_physical_apicid > 255 || !kvm_para_available())
+		if (max_physical_apicid > 255 ||
+		    !hypervisor_x2apic_available())
 			goto nox2apic;
 		/*
 		 * without IR all CPUs can be addressed by IOAPIC/MSI
-- 
1.7.0.1

Re: [PATCH 1/2] apic: Move hypervisor detection of x2apic to hypervisor.h

[Sheng Yang]

On Wednesday 08 December 2010 14:03:59 Sheng Yang wrote:
> Signed-off-by: Sheng Yang <sheng@linux.intel.com>
> ---

Jeremy?

--
regards
Yang, Sheng

>  arch/x86/include/asm/hypervisor.h |    9 +++++++++
>  arch/x86/kernel/apic/apic.c       |    5 +++--
>  2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/hypervisor.h
> b/arch/x86/include/asm/hypervisor.h index ff2546c..0c6f7af 100644
> --- a/arch/x86/include/asm/hypervisor.h
> +++ b/arch/x86/include/asm/hypervisor.h
> @@ -20,6 +20,8 @@
>  #ifndef _ASM_X86_HYPERVISOR_H
>  #define _ASM_X86_HYPERVISOR_H
> 
> +#include <asm/kvm_para.h>
> +
>  extern void init_hypervisor(struct cpuinfo_x86 *c);
>  extern void init_hypervisor_platform(void);
> 
> @@ -47,4 +49,11 @@ extern const struct hypervisor_x86 x86_hyper_vmware;
>  extern const struct hypervisor_x86 x86_hyper_ms_hyperv;
>  extern const struct hypervisor_x86 x86_hyper_xen_hvm;
> 
> +static inline bool hypervisor_x2apic_available(void)
> +{
> +	if (kvm_para_available())
> +		return true;
> +	return false;
> +}
> +
>  #endif
> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
> index 3f838d5..8408f2d 100644
> --- a/arch/x86/kernel/apic/apic.c
> +++ b/arch/x86/kernel/apic/apic.c
> @@ -50,8 +50,8 @@
>  #include <asm/mtrr.h>
>  #include <asm/smp.h>
>  #include <asm/mce.h>
> -#include <asm/kvm_para.h>
>  #include <asm/tsc.h>
> +#include <asm/hypervisor.h>
> 
>  unsigned int num_processors;
> 
> @@ -1476,7 +1476,8 @@ void __init enable_IR_x2apic(void)
>  		/* IR is required if there is APIC ID > 255 even when running
>  		 * under KVM
>  		 */
> -		if (max_physical_apicid > 255 || !kvm_para_available())
> +		if (max_physical_apicid > 255 ||
> +		    !hypervisor_x2apic_available())
>  			goto nox2apic;
>  		/*
>  		 * without IR all CPUs can be addressed by IOAPIC/MSI