Sheng Yang wrote: > From 00a52112d813af983dd4d34cb7dc701f6fe88829 Mon Sep 17 00:00:00 2001 > From: Sheng Yang <[EMAIL PROTECTED]> > Date: Fri, 2 Nov 2007 11:56:17 +0800 > Subject: [PATCH] KVM: VMX: Fix repeatly calling alloc_apic_access_page() > > For SMP guest, alloc_apic_access_page() would be called more than once. So > only the last vcpu's vmcs get correct apic access address, causing SMP guest > can't benifit from FlexPriority. > > This patch fixed this issue. > > Signed-off-by: Sheng Yang <[EMAIL PROTECTED]> > --- > drivers/kvm/kvm_main.c | 1 + > drivers/kvm/vmx.c | 5 ++++- > 2 files changed, 5 insertions(+), 1 deletions(-) > > diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c > index 34a681d..519626d 100644 > --- a/drivers/kvm/kvm_main.c > +++ b/drivers/kvm/kvm_main.c > @@ -245,6 +245,7 @@ static struct kvm *kvm_create_vm(void) > spin_lock(&kvm_lock); > list_add(&kvm->vm_list, &vm_list); > spin_unlock(&kvm_lock); > + kvm->apic_access_page = NULL; >
Seems unnecessary, since the whole thing is kzalloc()ed? > return kvm; > } > > diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c > index 42e7fad..89007b2 100644 > --- a/drivers/kvm/vmx.c > +++ b/drivers/kvm/vmx.c > @@ -1466,6 +1466,8 @@ static int alloc_apic_access_page(struct kvm *kvm) > int r; > > r = -EFAULT; > + if (kvm->apic_access_page) > + return 0; > Racy, what if two vcpus are created simultaneously? > kvm_userspace_mem.slot = APIC_ACCESS_PAGE_PRIVATE_MEMSLOT; > kvm_userspace_mem.flags = 0; > kvm_userspace_mem.guest_phys_addr = 0xfee00000ULL; > @@ -1584,7 +1586,8 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx) > vmcs_writel(CR0_GUEST_HOST_MASK, ~0UL); > vmcs_writel(CR4_GUEST_HOST_MASK, KVM_GUEST_CR4_MASK); > > - if (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm)) > + if ((vmx->vcpu.vcpu_id == 0) && > + (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm))) > if (alloc_apic_access_page(vmx->vcpu.kvm) != 0) > return -ENOMEM; > > We may not have vcpu id 0 (though it's very unlikely). I think the problems arise because we are doing a VM-wide operation (memory slot) from a vcpu context. I think adding a ->vm_create() arch op and allocating the memory there will be better (under kvm->lock). -- Any sufficiently difficult bug is indistinguishable from a feature. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ kvm-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kvm-devel
