Re: [Xen-devel] [PATCH 6 of 7] IOMMU: add crash_shutdown iommu_op

[Keir Fraser <keir@xxxxxxx>]

On 13/06/2011 18:02, "Andrew Cooper" <andrew.cooper3@xxxxxxxxxx> wrote:

> The kdump kernel has problems booting with interrupt/dma
> remapping enabled, so we need a new iommu_ops called
> crash_shutdown which is basically suspend but doesn't
> need to bother saving state.
> 
> Make sure that crash_shutdown is called on the kexec
> path.

What's wrong with the existing .suspend iommu callbacks? They look very
similar (identical in the AMD case in fact). The extra
iommu_disable_x2apic_IR() could be avoided in favour of the eisting one in
the lapic_suspend() path, perhaps?

 -- Keir

> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> 
> diff -r 2635774346c4 -r 3ad737eb0a8d xen/arch/x86/crash.c
> --- a/xen/arch/x86/crash.c Mon Jun 13 17:45:43 2011 +0100
> +++ b/xen/arch/x86/crash.c Mon Jun 13 17:45:43 2011 +0100
> @@ -77,6 +77,10 @@ static void nmi_shootdown_cpus(void)
>          msecs--;
>      }
>  
> +    /* Crash shutdown any IOMMU functionality as the crashdump kernel is not
> +     * happy when booting if interrupt/dma remapping is still enabled */
> +    iommu_crash_shutdown();
> +
>      __stop_this_cpu();
>      disable_IO_APIC();
>  
> diff -r 2635774346c4 -r 3ad737eb0a8d xen/drivers/passthrough/amd/iommu_init.c
> --- a/xen/drivers/passthrough/amd/iommu_init.c Mon Jun 13 17:45:43 2011 +0100
> +++ b/xen/drivers/passthrough/amd/iommu_init.c Mon Jun 13 17:45:43 2011 +0100
> @@ -921,6 +921,14 @@ void amd_iommu_suspend(void)
>          disable_iommu(iommu);
>  }
>  
> +void amd_iommu_crash_shutdown(void)
> +{
> +    struct amd_iommu *iommu;
> +
> +    for_each_amd_iommu ( iommu )
> +        disable_iommu(iommu);
> +}
> +
>  void amd_iommu_resume(void)
>  {
>      struct amd_iommu *iommu;
> diff -r 2635774346c4 -r 3ad737eb0a8d
> xen/drivers/passthrough/amd/pci_amd_iommu.c
> --- a/xen/drivers/passthrough/amd/pci_amd_iommu.c Mon Jun 13 17:45:43 2011
> +0100
> +++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c Mon Jun 13 17:45:43 2011
> +0100
> @@ -459,4 +459,5 @@ const struct iommu_ops amd_iommu_ops = {
>      .suspend = amd_iommu_suspend,
>      .resume = amd_iommu_resume,
>      .share_p2m = amd_iommu_share_p2m,
> +    .crash_shutdown = amd_iommu_crash_shutdown,
>  };
> diff -r 2635774346c4 -r 3ad737eb0a8d xen/drivers/passthrough/iommu.c
> --- a/xen/drivers/passthrough/iommu.c Mon Jun 13 17:45:43 2011 +0100
> +++ b/xen/drivers/passthrough/iommu.c Mon Jun 13 17:45:43 2011 +0100
> @@ -429,6 +429,14 @@ void iommu_share_p2m_table(struct domain
>          ops->share_p2m(d);
>  }
>  
> +void iommu_crash_shutdown(void)
> +{
> +    const struct iommu_ops *ops = iommu_get_ops();
> +    if ( ops && ops->crash_shutdown )
> +        ops->crash_shutdown();
> +    iommu_enabled = 0;
> +}
> +
>  /*
>   * Local variables:
>   * mode: C
> diff -r 2635774346c4 -r 3ad737eb0a8d xen/drivers/passthrough/vtd/iommu.c
> --- a/xen/drivers/passthrough/vtd/iommu.c Mon Jun 13 17:45:43 2011 +0100
> +++ b/xen/drivers/passthrough/vtd/iommu.c Mon Jun 13 17:45:43 2011 +0100
> @@ -2238,6 +2238,25 @@ static void vtd_suspend(void)
>      }
>  }
>  
> +static void vtd_crash_shutdown(void)
> +{
> +    struct acpi_drhd_unit *drhd;
> +    struct iommu *iommu;
> +
> +    if ( !iommu_enabled )
> +        return;
> +
> +    iommu_flush_all();
> +
> +    for_each_drhd_unit ( drhd )
> +    {
> +        iommu = drhd->iommu;
> +        iommu_disable_translation(iommu);
> +    }
> +
> +    iommu_disable_x2apic_IR();
> +}
> +
>  static void vtd_resume(void)
>  {
>      struct acpi_drhd_unit *drhd;
> @@ -2289,6 +2308,7 @@ const struct iommu_ops intel_iommu_ops =
>      .suspend = vtd_suspend,
>      .resume = vtd_resume,
>      .share_p2m = iommu_set_pgd,
> +    .crash_shutdown = vtd_crash_shutdown,
>  };
>  
>  /*
> diff -r 2635774346c4 -r 3ad737eb0a8d
> xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
> --- a/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h Mon Jun 13 17:45:43 2011
> +0100
> +++ b/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h Mon Jun 13 17:45:43 2011
> +0100
> @@ -98,6 +98,7 @@ unsigned int amd_iommu_read_ioapic_from_
>  /* power management support */
>  void amd_iommu_resume(void);
>  void amd_iommu_suspend(void);
> +void amd_iommu_crash_shutdown(void);
>  
>  static inline u32 get_field_from_reg_u32(u32 reg_value, u32 mask, u32 shift)
>  {
> diff -r 2635774346c4 -r 3ad737eb0a8d xen/include/xen/iommu.h
> --- a/xen/include/xen/iommu.h Mon Jun 13 17:45:43 2011 +0100
> +++ b/xen/include/xen/iommu.h Mon Jun 13 17:45:43 2011 +0100
> @@ -133,6 +133,7 @@ struct iommu_ops {
>      void (*suspend)(void);
>      void (*resume)(void);
>      void (*share_p2m)(struct domain *d);
> +    void (*crash_shutdown)(void);
>  };
>  
>  void iommu_update_ire_from_apic(unsigned int apic, unsigned int reg, unsigned
> int value);
> @@ -142,6 +143,7 @@ unsigned int iommu_read_apic_from_ire(un
>  
>  void iommu_suspend(void);
>  void iommu_resume(void);
> +void iommu_crash_shutdown(void);
>  
>  void iommu_set_dom0_mapping(struct domain *d);
>  void iommu_share_p2m_table(struct domain *d);
> 
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