linux-kernel - [PATCH linux v3 5/9] x86/xen: use xen_vcpu_id mapping when pointing vcpu_info to the shared

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Date:	Tue, 26 Jul 2016 14:30:24 +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>,
	"Jan Beulich" <JBeulich@...e.com>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	Julien Grall <julien.grall@....com>
Subject: [PATCH linux v3 5/9] 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>
---
Changes since v1:
- Use xen_vcpu_nr() helper [David Vrabel]
---
 arch/x86/xen/enlighten.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 3b0ceed..c650677 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -207,8 +207,9 @@ 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_vcpu_nr(cpu) < MAX_VIRT_CPUS)
+		per_cpu(xen_vcpu, cpu) =
+			&HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
 
 	if (!have_vcpu_info_placement) {
 		if (cpu >= MAX_VIRT_CPUS)
@@ -1781,9 +1782,10 @@ void __ref xen_hvm_init_shared_info(void)
 	 * in that case multiple vcpus might be online. */
 	for_each_online_cpu(cpu) {
 		/* Leave it to be NULL. */
-		if (cpu >= MAX_VIRT_CPUS)
+		if (xen_vcpu_nr(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_vcpu_nr(cpu)];
 	}
 }
 
-- 
2.7.4