> -----Original Message-----
> From: Andrew Cooper [mailto:[email protected]]
> Sent: Friday, March 27, 2015 3:17 AM
> To: Wu, Feng; [email protected]
> Cc: Zhang, Yang Z; Tian, Kevin; [email protected]; [email protected]
> Subject: Re: [Xen-devel] [RFC v1 07/15] vt-d: Add API to update IRTE when VT-d
> PI is used
>
> On 25/03/15 12:31, Feng Wu wrote:
> > This patch adds an API which is used to update the IRTE
> > for posted-interrupt when guest changes MSI/MSI-X information.
> >
> > Signed-off-by: Feng Wu <[email protected]>
> > ---
> > xen/drivers/passthrough/vtd/intremap.c | 83
> ++++++++++++++++++++++++++++++++++
> > xen/drivers/passthrough/vtd/iommu.h | 3 ++
> > xen/include/asm-x86/iommu.h | 2 +
> > 3 files changed, 88 insertions(+)
> >
> > diff --git a/xen/drivers/passthrough/vtd/intremap.c
> b/xen/drivers/passthrough/vtd/intremap.c
> > index 0333686..f44e74d 100644
> > --- a/xen/drivers/passthrough/vtd/intremap.c
> > +++ b/xen/drivers/passthrough/vtd/intremap.c
> > @@ -898,3 +898,86 @@ void iommu_disable_x2apic_IR(void)
> > for_each_drhd_unit ( drhd )
> > disable_qinval(drhd->iommu);
> > }
> > +
> > +/*
> > + * This function is used to update the IRTE for posted-interrupt
> > + * when guest changes MSI/MSI-X information
> > + */
> > +int pi_update_irte(struct vcpu *v, struct pirq *pirq, uint32_t gvec )
>
> Stray space after gvec.
>
> I presume gvec means "guest vector", in which case it should be a uint8_t.
>
> > +{
> > + struct irq_desc *desc;
> > + struct msi_desc *msi_desc;
> > + int remap_index, rc = -1;
> > + struct pci_dev *pci_dev;
> > + struct acpi_drhd_unit *drhd;
> > + struct iommu *iommu;
> > + struct ir_ctrl *ir_ctrl;
> > + struct iremap_entry *iremap_entries = NULL, *p = NULL;
> > + struct iremap_entry new_ire;
> > + struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
> > + unsigned long flags;
> > +
> > + desc = pirq_spin_lock_irq_desc(pirq, NULL);
> > + if ( !desc )
> > + return -1;
> > +
> > + msi_desc = desc->msi_desc;
> > + if ( !msi_desc )
> > + goto unlock_out;
> > +
> > + remap_index = msi_desc->remap_index;
> > + pci_dev = msi_desc->dev;
> > + if ( !pci_dev )
> > + goto unlock_out;
> > +
> > + drhd = acpi_find_matched_drhd_unit(pci_dev);
>
> This does an O(n^2) walk over the dhrd_units list and the unit
> device_cnt. As the layout will be completely static, might it be better
> to stash drhd information in struct pci_dev during boot?
This might be a good suggestion. Since acpi_find_matched_drhd_unit() is widely
used in the current code for this purpose, I think we can define this as an
independent
work if this is really doable.
Thanks,
Feng
>
> > + if (!drhd)
>
> Spaces inside brackets.
>
> > + {
> > + dprintk(XENLOG_INFO VTDPREFIX, "failed to get drhd!\n");
>
> This is a useless error message, providing no useful information to
> identify the issue.
>
> At the very least it should identify the domain and vcpu (%pv of v), the
> guest vector and pci device. Also, drop the exclamation mark - it is
> not useful in the log.
>
> > + goto unlock_out;
> > + }
> > +
> > + iommu = drhd->iommu;
> > + ir_ctrl = iommu_ir_ctrl(iommu);
> > + if ( !ir_ctrl )
> > + {
> > + dprintk(XENLOG_INFO VTDPREFIX, "failed to get ir_ctrl!\n");
>
> Needs simiarly extending with some information.
>
> > + goto unlock_out;
> > + }
> > +
> > + spin_lock_irqsave(&ir_ctrl->iremap_lock, flags);
> > +
> > + GET_IREMAP_ENTRY(ir_ctrl->iremap_maddr, remap_index,
> iremap_entries, p);
> > +
> > + memcpy(&new_ire, p, sizeof(struct iremap_entry));
>
> sizeof(new_ire) please
>
> > +
> > + /* Setup/Update interrupt remapping table entry */
> > + new_ire.lo_intpost.urg = 0;
> > + new_ire.lo_intpost.vector = gvec;
> > + new_ire.lo_intpost.pda_l = (((u64)virt_to_maddr(pi_desc)) >>
> > + (32 - PDA_LOW_BIT)) & ~(-1UL <<
> PDA_LOW_BIT);
> > + new_ire.hi_intpost.pda_h = (((u64)virt_to_maddr(pi_desc)) >> 32) &
> > + ~(-1UL << PDA_HIGH_BIT);
>
> Is it possible to hide this bit manipulation in side a static inline
> function which takes an ire and pi_desc pointer rather than open coding it?
>
> > +
> > + new_ire.lo_intpost.res_1 = 0;
> > + new_ire.lo_intpost.res_2 = 0;
> > + new_ire.lo_intpost.res_3 = 0;
> > + new_ire.hi_intpost.res_1 = 0;
> > +
> > + new_ire.lo_intpost.im = 1;
> > +
> > + memcpy(p, &new_ire, sizeof(struct iremap_entry));
> > + iommu_flush_cache_entry(p, sizeof(struct iremap_entry));
>
> Same here regarding sizeof.
>
> Furthermore, is the memcpy() safe to update the live descriptor?
>
> If it is, why do you not update the descriptor in place using p-> rather
> than copying it to the stack and back?
>
> ~Andrew
>
> > + iommu_flush_iec_index(iommu, 0, remap_index);
> > +
> > + if ( iremap_entries )
> > + unmap_vtd_domain_page(iremap_entries);
> > +
> > + spin_unlock_irqrestore(&ir_ctrl->iremap_lock, flags);
> > +
> > + rc = 0;
> > + unlock_out:
> > + spin_unlock_irq(&desc->lock);
> > +
> > + return rc;
> > +}
> > diff --git a/xen/drivers/passthrough/vtd/iommu.h
> b/xen/drivers/passthrough/vtd/iommu.h
> > index cd61e12..ffa72c8 100644
> > --- a/xen/drivers/passthrough/vtd/iommu.h
> > +++ b/xen/drivers/passthrough/vtd/iommu.h
> > @@ -334,6 +334,9 @@ struct iremap_entry {
> > };
> > };
> >
> > +#define PDA_LOW_BIT 26
> > +#define PDA_HIGH_BIT 32
> > +
> > /* Max intr remapping table page order is 8, as max number of IRTEs is
> 64K */
> > #define IREMAP_PAGE_ORDER 8
> >
> > diff --git a/xen/include/asm-x86/iommu.h b/xen/include/asm-x86/iommu.h
> > index e7a65da..d233621 100644
> > --- a/xen/include/asm-x86/iommu.h
> > +++ b/xen/include/asm-x86/iommu.h
> > @@ -32,6 +32,8 @@ int iommu_supports_eim(void);
> > int iommu_enable_x2apic_IR(void);
> > void iommu_disable_x2apic_IR(void);
> >
> > +int pi_update_irte(struct vcpu *v, struct pirq *pirq, uint32_t gvec);
> > +
> > #endif /* !__ARCH_X86_IOMMU_H__ */
> > /*
> > * Local variables:
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