linux-kernel - [PATCH linux 4/8] x86/xen: use xen_vcpu_id mapping when pointing vcpu_info to the shared

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Date:	Tue, 28 Jun 2016 18:47:25 +0200
From:	Vitaly Kuznetsov <vkuznets@...hat.com>
To:	xen-devel@...ts.xenproject.org
Cc:	linux-kernel@...r.kernel.org, x86@...nel.org,
	Stefano Stabellini <sstabellini@...nel.org>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	David Vrabel <david.vrabel@...rix.com>,
	Juergen Gross <jgross@...e.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Julien Grall <julien.grall@...rix.com>
Subject: [PATCH linux 4/8] x86/xen: use xen_vcpu_id mapping when pointing vcpu_info to the shared_info page

shared_info page has space for 32 vcpu info slots for first 32 vCPUs but
these are the first 32 vCPUs from Xen's perspective and we should map them
accordingly with the newly introduced xen_vcpu_id mapping.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 arch/x86/xen/enlighten.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 69f4c0c..1596626 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -189,6 +189,7 @@ static void xen_vcpu_setup(int cpu)
 	struct vcpu_register_vcpu_info info;
 	int err;
 	struct vcpu_info *vcpup;
+	int xen_cpu = per_cpu(xen_vcpu_id, cpu);
 
 	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
 
@@ -207,8 +208,9 @@ static void xen_vcpu_setup(int cpu)
 		if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
 			return;
 	}
-	if (cpu < MAX_VIRT_CPUS)
-		per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
+	if (xen_cpu < MAX_VIRT_CPUS)
+		per_cpu(xen_vcpu, cpu) =
+			&HYPERVISOR_shared_info->vcpu_info[xen_cpu];
 
 	if (!have_vcpu_info_placement) {
 		if (cpu >= MAX_VIRT_CPUS)
@@ -1752,7 +1754,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
 
 void __ref xen_hvm_init_shared_info(void)
 {
-	int cpu;
+	int cpu, xen_cpu;
 	struct xen_add_to_physmap xatp;
 	static struct shared_info *shared_info_page = 0;
 
@@ -1777,10 +1779,13 @@ void __ref xen_hvm_init_shared_info(void)
 	 * online but xen_hvm_init_shared_info is run at resume time too and
 	 * in that case multiple vcpus might be online. */
 	for_each_online_cpu(cpu) {
+		xen_cpu = per_cpu(xen_vcpu_id, cpu);
+
 		/* Leave it to be NULL. */
-		if (cpu >= MAX_VIRT_CPUS)
+		if (xen_cpu >= MAX_VIRT_CPUS)
 			continue;
-		per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
+		per_cpu(xen_vcpu, cpu) =
+			&HYPERVISOR_shared_info->vcpu_info[xen_cpu];
 	}
 }
 
-- 
2.5.5