RE: [v3 12/26] KVM: Initialize VT-d Posted-Interrupts Descriptor

[Zhang, Yang Z]

Feng Wu wrote on 2014-12-12:
> This patch initializes the VT-d Posted-Interrupts Descriptor.
> 
> Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
> ---
>  arch/x86/kvm/vmx.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index
> 0b1383e..66ca275 100644 --- a/arch/x86/kvm/vmx.c +++
> b/arch/x86/kvm/vmx.c @@ -45,6 +45,7 @@
>  #include <asm/perf_event.h>
>  #include <asm/debugreg.h>
>  #include <asm/kexec.h>
> +#include <asm/irq_remapping.h>
> 
>  #include "trace.h"
> @@ -4433,6 +4434,30 @@ static void ept_set_mmio_spte_mask(void)
>  	kvm_mmu_set_mmio_spte_mask((0x3ull << 62) | 0x6ull);  }
> +static void pi_desc_init(struct vcpu_vmx *vmx) {
> +	unsigned int dest;
> +
> +	if (!irq_remapping_cap(IRQ_POSTING_CAP))
> +		return;
> +
> +	/*
> +	 * Initialize Posted-Interrupt Descriptor
> +	 */
> +
> +	pi_clear_sn(&vmx->pi_desc);
> +	vmx->pi_desc.nv = POSTED_INTR_VECTOR;

Here.

> +
> +	/* Physical mode for Notificaiton Event */
> +	vmx->pi_desc.ndm = 0;

And from here..

> +	dest = cpu_physical_id(vmx->vcpu.cpu);
> +
> +	if (x2apic_enabled())
> +		vmx->pi_desc.ndst = dest;
> +	else
> +		vmx->pi_desc.ndst = (dest << 8) & 0xFF00; }
> +

..to here are useless. The right place to update PI descriptor is where vcpu got loaded not in initialization.

>  /*
>   * Sets up the vmcs for emulated real mode.
>   */
> @@ -4476,6 +4501,8 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
> 
>  		vmcs_write64(POSTED_INTR_NV, POSTED_INTR_VECTOR);
>  		vmcs_write64(POSTED_INTR_DESC_ADDR, __pa((&vmx->pi_desc)));
> +
> +		pi_desc_init(vmx);
>  	}
>  
>  	if (ple_gap) {


Best regards,
Yang


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