On Sunday 04 November 2007 15:46:18 Avi Kivity wrote: > 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?
Yeah, that's right. I missed it. > > > 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? I think it is not racy, for BSP have been created before APs in sequence, and I am ensure only BSP(vcpu id=0) would call this. > > > 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). Um... I am not quite understand when we will miss vcpu id 0. I think vcpu id 0 is used to indicate BSP. > > 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). Agree, but a little problem remains. I have to do feature detection before call allocate function, but kvm_create_vm() is called before kvm_create_irqchip(). So I can't find a proper position for create_vm(). Any suggestion? -- Thanks Yang, Sheng ------------------------------------------------------------------------- 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
