From 3130f964bad10c85c17b1e28ed9b278745a905b9 Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Fri, 9 Jul 2010 12:22:35 +0100 Subject: [PATCH] xen: allow HVM save/restore from different cpus The hardware CPUID-levelling features level the feature flags but don't change the CPU family/model/stepping. Relax the HVM restore check on family/model/stepping to printk but not veto the load, so that VMs can be migrated between machines that have been CPUID-levelled. Signed-off-by: Tim Deegan --- xen/arch/x86/hvm/save.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/xen/arch/x86/hvm/save.c b/xen/arch/x86/hvm/save.c index 3fc24a0263..bc1b51647c 100644 --- a/xen/arch/x86/hvm/save.c +++ b/xen/arch/x86/hvm/save.c @@ -55,10 +55,11 @@ int arch_hvm_load(struct domain *d, struct hvm_save_header *hdr) } cpuid(1, &eax, &ebx, &ecx, &edx); - /* TODO: need to define how big a difference is acceptable? */ - if ( hdr->cpuid != eax ) - gdprintk(XENLOG_WARNING, "HVM restore: saved CPUID (%#"PRIx32") " - "does not match host (%#"PRIx32").\n", hdr->cpuid, eax); + /* CPUs ought to match but with feature-masking they might not */ + if ( (hdr->cpuid & ~0x0fUL) != (eax & ~0x0fUL) ) + gdprintk(XENLOG_INFO, "HVM restore (%u): VM saved on one CPU " + "(%#"PRIx32") and restored on another (%#"PRIx32").\n", + d->domain_id, hdr->cpuid, eax); /* Restore guest's preferred TSC frequency. */ if ( hdr->gtsc_khz ) -- 2.30.2