[PATCH linux v2 9/9] xen/pvhvm: run xen_vcpu_setup() for the boot CPU

[Vitaly Kuznetsov]

Historically we didn't call VCPUOP_register_vcpu_info for CPU0 for PVHVM
guests (while we had it for PV and ARM guests). This is usually fine as we
can use vcpu info in the sared_info page but when we try booting on a vCPU
with Xen's vCPU id > 31 (e.g. when we try to kdump after crashing on this
CPU) we're not able to boot. Switch to always doing
VCPUOP_register_vcpu_info for the boot CPU.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
 arch/x86/xen/enlighten.c | 2 +-
 arch/x86/xen/smp.c       | 7 +++++++
 arch/x86/xen/xen-ops.h   | 1 +
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index bfdd51b..7c91631 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -184,7 +184,7 @@ static void clamp_max_cpus(void)
 #endif
 }
 
-static void xen_vcpu_setup(int cpu)
+void xen_vcpu_setup(int cpu)
 {
 	struct vcpu_register_vcpu_info info;
 	int err;
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index a3118f2..0b4d04c 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -322,6 +322,13 @@ static void __init xen_smp_prepare_boot_cpu(void)
 		xen_filter_cpu_maps();
 		xen_setup_vcpu_info_placement();
 	}
+
+	/*
+	 * Setup vcpu_info for boot CPU.
+	 */
+	if (xen_hvm_domain())
+		xen_vcpu_setup(0);
+
 	/*
 	 * The alternative logic (which patches the unlock/lock) runs before
 	 * the smp bootup up code is activated. Hence we need to set this up
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 4140b07..3cbce3b 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -76,6 +76,7 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id);
 
 bool xen_vcpu_stolen(int vcpu);
 
+void xen_vcpu_setup(int cpu);
 void xen_setup_vcpu_info_placement(void);
 
 #ifdef CONFIG_SMP
-- 
2.5.5