Re: [PATCH] KVM: VMX: Add VMCS to CPU's loaded VMCSs before VMPTRLD

["Radim Krčmář" <rkrcmar@redhat.com>]

2016-07-29 18:56-0700, Jim Mattson:
> Kexec needs to know the addresses of all VMCSs that are active on
> each CPU, so that it can flush them from the VMCS caches. It is
> safe to record superfluous addresses that are not associated with
> an active VMCS, but it is not safe to omit an address associated
> with an active VMCS.
> 
> After a call to vmcs_load, the VMCS that was loaded is active on
> the CPU. The VMCS should be added to the CPU's list of active
> VMCSs before it is loaded.
> 
> Signed-off-by: Jim Mattson <jmattson@google.com>
> ---

Applied to kvm/queue, thanks.

I have tentatively kept the patch without "Cc: stable@..." as VMX might
not write to the in-memory VMCS unless the cached VMCS has been dirtied.

>  arch/x86/kvm/vmx.c | 26 +++++++++++++++-----------
>  1 file changed, 15 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 7758680..f3d9995 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -2121,22 +2121,14 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>  {
>  	struct vcpu_vmx *vmx = to_vmx(vcpu);
>  	u64 phys_addr = __pa(per_cpu(vmxarea, cpu));
> +	bool already_loaded = vmx->loaded_vmcs->cpu == cpu;
>  
>  	if (!vmm_exclusive)
>  		kvm_cpu_vmxon(phys_addr);
> -	else if (vmx->loaded_vmcs->cpu != cpu)
> +	else if (!already_loaded)
>  		loaded_vmcs_clear(vmx->loaded_vmcs);
>  
> -	if (per_cpu(current_vmcs, cpu) != vmx->loaded_vmcs->vmcs) {
> -		per_cpu(current_vmcs, cpu) = vmx->loaded_vmcs->vmcs;
> -		vmcs_load(vmx->loaded_vmcs->vmcs);
> -	}
> -
> -	if (vmx->loaded_vmcs->cpu != cpu) {
> -		struct desc_ptr *gdt = this_cpu_ptr(&host_gdt);
> -		unsigned long sysenter_esp;
> -
> -		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
> +	if (!already_loaded) {
>  		local_irq_disable();
>  		crash_disable_local_vmclear(cpu);
>  
> @@ -2151,6 +2143,18 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>  			 &per_cpu(loaded_vmcss_on_cpu, cpu));
>  		crash_enable_local_vmclear(cpu);
>  		local_irq_enable();
> +	}
> +
> +	if (per_cpu(current_vmcs, cpu) != vmx->loaded_vmcs->vmcs) {
> +		per_cpu(current_vmcs, cpu) = vmx->loaded_vmcs->vmcs;
> +		vmcs_load(vmx->loaded_vmcs->vmcs);
> +	}
> +
> +	if (!already_loaded) {
> +		struct desc_ptr *gdt = this_cpu_ptr(&host_gdt);
> +		unsigned long sysenter_esp;
> +
> +		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
>  
>  		/*
>  		 * Linux uses per-cpu TSS and GDT, so set these when switching
> -- 
> 2.8.0.rc3.226.g39d4020
> 
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