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* [PATCH] xen PVonHVM: require at least Xen 3.4 as dom0
@ 2012-10-30 16:05 Olaf Hering
  2012-10-30 18:17 ` Pasi Kärkkäinen
  0 siblings, 1 reply; 9+ messages in thread
From: Olaf Hering @ 2012-10-30 16:05 UTC (permalink / raw)
  To: Jeremy Fitzhardinge, Konrad Rzeszutek Wilk
  Cc: linux-kernel, xen-devel, Olaf Hering

The XenPVHVM extensions have not been tested much on very old
hypervisors. At least Xen 3.4 gets some testing with the pvops kernel.

Require at least Xen 3.4 for the PVonHVM extensions. If an older
hypervisor is detected the extensions will be disabled and the guest
will only see emulated hardware.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 arch/x86/xen/enlighten.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 0cc41f8..8566fa8 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1543,17 +1543,10 @@ static void __init xen_hvm_init_shared_info(void)
 
 static void __init init_hvm_pv_info(void)
 {
-	int major, minor;
 	uint32_t eax, ebx, ecx, edx, pages, msr, base;
 	u64 pfn;
 
 	base = xen_cpuid_base();
-	cpuid(base + 1, &eax, &ebx, &ecx, &edx);
-
-	major = eax >> 16;
-	minor = eax & 0xffff;
-	printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
-
 	cpuid(base + 2, &pages, &msr, &ecx, &edx);
 
 	pfn = __pa(hypercall_page);
@@ -1604,13 +1597,29 @@ static void __init xen_hvm_guest_init(void)
 
 static bool __init xen_hvm_platform(void)
 {
+	int major, minor, old = 0;
+	uint32_t eax, ebx, ecx, edx, base;
+	bool usable = true;
+
 	if (xen_pv_domain())
 		return false;
 
-	if (!xen_cpuid_base())
+	base = xen_cpuid_base();
+	if (!base)
 		return false;
 
-	return true;
+	cpuid(base + 1, &eax, &ebx, &ecx, &edx);
+
+	major = eax >> 16;
+	minor = eax & 0xffff;
+
+	/* Require at least Xen 3.4 */
+	if (major < 3 || (major == 3 && minor < 4))
+		usable = false;
+	printk(KERN_INFO "Xen version %d.%d.%s\n",
+		major, minor, usable ? "" : " (too old)");
+
+	return usable;
 }
 
 bool xen_hvm_need_lapic(void)
-- 
1.8.0

^ permalink raw reply related	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2012-10-31 11:48 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-10-30 16:05 [PATCH] xen PVonHVM: require at least Xen 3.4 as dom0 Olaf Hering
2012-10-30 18:17 ` Pasi Kärkkäinen
2012-10-30 18:28   ` [Xen-devel] " Olaf Hering
2012-10-31  8:30     ` Ian Campbell
2012-10-31  9:29       ` Olaf Hering
2012-10-31 10:21         ` Pasi Kärkkäinen
2012-10-31 11:48           ` Pasi Kärkkäinen
2012-10-31 10:25         ` Ian Campbell
2012-10-31  9:56   ` Olaf Hering

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