Re: [PATCH v2 1/5] VMX: fix interaction of APIC-V and Viridian emulation

[Andrew Cooper <andrew.cooper3@citrix.com>]

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On 24/06/13 08:03, Jan Beulich wrote:
> Viridian using a synthetic MSR for issuing EOI notifications bypasses
> the normal in-processor handling, which would clear
> GUEST_INTR_STATUS.SVI. Hence we need to do this in software in order
> for future interrupts to get delivered.
>
> Based on analysis by Yang Z Zhang <yang.z.zhang@intel.com>.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

> ---
> v2: Split off cleanup parts to new patch 3.
>
> --- a/xen/arch/x86/hvm/vlapic.c
> +++ b/xen/arch/x86/hvm/vlapic.c
> @@ -386,6 +386,9 @@ void vlapic_EOI_set(struct vlapic *vlapi
>  
>      vlapic_clear_vector(vector, &vlapic->regs->data[APIC_ISR]);
>  
> +    if ( hvm_funcs.handle_eoi )
> +        hvm_funcs.handle_eoi(vector);
> +
>      if ( vlapic_test_and_clear_vector(vector, &vlapic->regs->data[APIC_TMR]) )
>          vioapic_update_EOI(vlapic_domain(vlapic), vector);
>  
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -1502,6 +1502,15 @@ static void vmx_sync_pir_to_irr(struct v
>          vlapic_set_vector(i, &vlapic->regs->data[APIC_IRR]);
>  }
>  
> +static void vmx_handle_eoi(u8 vector)
> +{
> +    unsigned long status = __vmread(GUEST_INTR_STATUS);
> +
> +    /* We need to clear the SVI field. */
> +    status &= VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK;
> +    __vmwrite(GUEST_INTR_STATUS, status);
> +}
> +
>  static struct hvm_function_table __initdata vmx_function_table = {
>      .name                 = "VMX",
>      .cpu_up_prepare       = vmx_cpu_up_prepare,
> @@ -1554,6 +1563,7 @@ static struct hvm_function_table __initd
>      .process_isr          = vmx_process_isr,
>      .deliver_posted_intr  = vmx_deliver_posted_intr,
>      .sync_pir_to_irr      = vmx_sync_pir_to_irr,
> +    .handle_eoi           = vmx_handle_eoi,
>      .nhvm_hap_walk_L1_p2m = nvmx_hap_walk_L1_p2m,
>  };
>  
> @@ -1580,7 +1590,10 @@ const struct hvm_function_table * __init
>  
>          setup_ept_dump();
>      }
> - 
> +
> +    if ( !cpu_has_vmx_virtual_intr_delivery )
> +        vmx_function_table.handle_eoi = NULL;
> +
>      if ( cpu_has_vmx_posted_intr_processing )
>          alloc_direct_apic_vector(&posted_intr_vector, event_check_interrupt);
>      else
> --- a/xen/include/asm-x86/hvm/hvm.h
> +++ b/xen/include/asm-x86/hvm/hvm.h
> @@ -186,6 +186,7 @@ struct hvm_function_table {
>      void (*process_isr)(int isr, struct vcpu *v);
>      void (*deliver_posted_intr)(struct vcpu *v, u8 vector);
>      void (*sync_pir_to_irr)(struct vcpu *v);
> +    void (*handle_eoi)(u8 vector);
>  
>      /*Walk nested p2m  */
>      int (*nhvm_hap_walk_L1_p2m)(struct vcpu *v, paddr_t L2_gpa,
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel


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