Signed-off-by: Gregory Haskins <[EMAIL PROTECTED]> --- drivers/kvm/vmx.c | 70 +++++++++++++++++++++++++++++++++++++++++++---------- 1 files changed, 57 insertions(+), 13 deletions(-)
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index 5f0a7fd..d6354ca 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -188,6 +188,20 @@ static struct kvm_msr_entry *find_msr_entry(struct kvm_vcpu *vcpu, u32 msr) return NULL; } +static void vmcs_load(struct vmcs *vmcs) +{ + u64 phys_addr = __pa(vmcs); + u8 error; + + asm volatile (ASM_VMX_VMPTRLD_RAX "; setna %0" + : "=g"(error) : "a"(&phys_addr), "m"(phys_addr) + : "cc"); + + if (error) + printk(KERN_ERR "kvm: vmptrld %p/%llx fail\n", + vmcs, phys_addr); +} + static void vmcs_clear(struct vmcs *vmcs) { u64 phys_addr = __pa(vmcs); @@ -206,10 +220,34 @@ static void __vcpu_clear(void *arg) struct kvm_vcpu *vcpu = arg; int cpu = raw_smp_processor_id(); - if (vcpu->cpu == cpu) + if (vcpu->cpu != -1) { + /* + * We should *never* try to __vcpu_clear a remote VMCS. This + * would have been addressed at a higher layer already + */ + BUG_ON(vcpu->cpu != cpu); + + /* + * Execute the VMCLEAR operation regardless of whether the + * VMCS is currently active on this CPU or not (it doesn't + * necessarily have to be) + */ vmcs_clear(vmx(vcpu)->vmcs); - if (per_cpu(current_vmcs, cpu) == vmx(vcpu)->vmcs) - per_cpu(current_vmcs, cpu) = NULL; + + /* + * And finally, if this VMCS *was* currently active on this + * CPU, mark the CPU as available again + */ + if (per_cpu(current_vmcs, cpu) == vmx(vcpu)->vmcs) + per_cpu(current_vmcs, cpu) = NULL; + } else + /* + * If vcpu->cpu thinks we are not installed anywhere, + * but this CPU thinks are are currently active, something is + * wacked. + */ + BUG_ON(per_cpu(current_vmcs, cpu) == vmx(vcpu)->vmcs); + rdtscll(vcpu->host_tsc); } @@ -220,6 +258,7 @@ static void vcpu_clear(struct kvm_vcpu *vcpu) else __vcpu_clear(vcpu); vmx(vcpu)->launched = 0; + vcpu->cpu = -1; } static unsigned long vmcs_readl(unsigned long field) @@ -423,7 +462,6 @@ static void vmx_load_host_state(struct kvm_vcpu *vcpu) */ static void vmx_vcpu_load(struct kvm_vcpu *vcpu) { - u64 phys_addr = __pa(vmx(vcpu)->vmcs); int cpu; u64 tsc_this, delta; @@ -432,16 +470,22 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu) if (vcpu->cpu != cpu) vcpu_clear(vcpu); - if (per_cpu(current_vmcs, cpu) != vmx(vcpu)->vmcs) { - u8 error; - + /* + * By the time we get here, we know that either our VMCS is already + * loaded on the current CPU (from previous runs), or that its not + * loaded *anywhere* in the system at all (due to the vcpu_clear() + * operation above). Either way, we must check to make sure we are + * the currently loaded pointer, and correct it if we are not. + * + * Note: A race condition exists against current_vmcs between the + * following update, and any IPIs dispatched to clear a different + * VMCS. Currently, this race condition is believed to be benign, + * but tread carefully. + */ + if (per_cpu(current_vmcs, cpu) != vmx(vcpu)->vmcs) { + /* Re-establish ourselves as the current VMCS */ + vmcs_load(vmx(vcpu)->vmcs); per_cpu(current_vmcs, cpu) = vmx(vcpu)->vmcs; - asm volatile (ASM_VMX_VMPTRLD_RAX "; setna %0" - : "=g"(error) : "a"(&phys_addr), "m"(phys_addr) - : "cc"); - if (error) - printk(KERN_ERR "kvm: vmptrld %p/%llx fail\n", - vmx(vcpu)->vmcs, phys_addr); } if (vcpu->cpu != cpu) { ------------------------------------------------------------------------- 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 kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel