linux-kernel - Re: [PART2 PATCH v3 06/11] iommu/amd: Adding GALOG interrupt handler

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Message-ID: <20160711184712.GA1334@potion>
Date:	Mon, 11 Jul 2016 20:47:12 +0200
From:	Radim Krčmář <rkrcmar@...hat.com>
To:	Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Cc:	joro@...tes.org, pbonzini@...hat.com, alex.williamson@...hat.com,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	sherry.hurwitz@....com
Subject: Re: [PART2 PATCH v3 06/11] iommu/amd: Adding GALOG interrupt handler

2016-07-11 05:11-0500, Suravee Suthikulpanit:
> From: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
> 
> This patch adds AMD IOMMU guest virtual APIC log (GALOG) handler.
> When IOMMU hardware receives an interrupt targeting a blocking vcpu,
> it creates an entry in the GALOG, and generates an interrupt to notify
> the AMD IOMMU driver.
> 
> At this point, the driver processes the log entry, and notify the SVM
> driver via the registered iommu_ga_log_notifier function.
> 
> Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
> ---
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> @@ -741,14 +741,101 @@ static void iommu_poll_ppr_log(struct amd_iommu *iommu)
> +static void iommu_handle_ga_guest_nr_entry(struct amd_iommu *iommu,
> +					   u16 devid, u32 ga_tag)
> +{
> +	struct amd_ir_data *ir_data;
> +	unsigned long flags;
> +	int vec = 0;
> +
> +	if (!iommu_ga_log_notifier)
> +		return;
> +
> +	spin_lock_irqsave(&iommu->ga_hash_lock, flags);
> +	hash_for_each_possible(iommu->ga_hash, ir_data, hnode, ga_tag) {
> +		struct irte_ga *entry = (struct irte_ga *)ir_data->entry;

  if (ga_tag != entry->fields_vapic.ga_tag)
  	continue;

Multiple different ga_tags can map to the same bucket, so we need to
explicitly select the correct entry.

> +
> +		vec = entry->hi.fields.vector;
> +		break;
> +	}
> +	spin_unlock_irqrestore(&iommu->ga_hash_lock, flags);
> +
> +	if (vec) {
> +		pr_debug("AMD-Vi: %s: devid=%#x, ga_tag=%#x\n",
> +			 __func__, devid, ga_tag);
> +
> +		if (iommu_ga_log_notifier(GATAG_TO_AVICTAG(ga_tag),
> +					  GATAG_TO_VCPUID(ga_tag), vec) != 0)