[v9,3/7] vfio/type1: bypass unmap/unpin and replay for VFIO_IOVA_RESERVED slots

Message ID 1462362858-2925-4-git-send-email-eric.auger@linaro.org
State New
Headers show

Commit Message

Auger Eric May 4, 2016, 11:54 a.m.
Before allowing the end-user to create VFIO_IOVA_RESERVED dma slots,
let's implement the expected behavior for removal and replay. As opposed
to user dma slots, IOVAs are not systematically bound to PAs and PAs are
not pinned. VFIO just initializes the IOVA "aperture". IOVAs are allocated
outside of the VFIO framework, typically the MSI layer which is
responsible to free and unmap them. The MSI mapping resources are freeed
by the IOMMU driver on domain destruction.

Signed-off-by: Eric Auger <eric.auger@linaro.org>


---

v7 -> v8:
- do no destroy anything anymore, just bypass unmap/unpin and iommu_map
  on replay
---
 drivers/vfio/vfio_iommu_type1.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

-- 
1.9.1

Comments

Auger Eric May 11, 2016, 12:58 p.m. | #1
Hi Alex,
On 05/10/2016 12:49 AM, Alex Williamson wrote:
> On Wed,  4 May 2016 11:54:14 +0000

> Eric Auger <eric.auger@linaro.org> wrote:

> 

>> Before allowing the end-user to create VFIO_IOVA_RESERVED dma slots,

>> let's implement the expected behavior for removal and replay. As opposed

>> to user dma slots, IOVAs are not systematically bound to PAs and PAs are

>> not pinned. VFIO just initializes the IOVA "aperture". IOVAs are allocated

>> outside of the VFIO framework, typically the MSI layer which is

>> responsible to free and unmap them. The MSI mapping resources are freeed

>> by the IOMMU driver on domain destruction.

>>

>> Signed-off-by: Eric Auger <eric.auger@linaro.org>

>>

>> ---

>>

>> v7 -> v8:

>> - do no destroy anything anymore, just bypass unmap/unpin and iommu_map

>>   on replay

>> ---

>>  drivers/vfio/vfio_iommu_type1.c | 5 ++++-

>>  1 file changed, 4 insertions(+), 1 deletion(-)

>>

>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c

>> index 2d769d4..94a9916 100644

>> --- a/drivers/vfio/vfio_iommu_type1.c

>> +++ b/drivers/vfio/vfio_iommu_type1.c

>> @@ -391,7 +391,7 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)

>>  	struct vfio_domain *domain, *d;

>>  	long unlocked = 0;

>>  

>> -	if (!dma->size)

>> +	if (!dma->size || dma->type != VFIO_IOVA_USER)

>>  		return;

>>  	/*

>>  	 * We use the IOMMU to track the physical addresses, otherwise we'd

>> @@ -727,6 +727,9 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu,

>>  		dma = rb_entry(n, struct vfio_dma, node);

>>  		iova = dma->iova;

>>  

>> +		if (dma->type == VFIO_IOVA_RESERVED)

>> +			continue;

>> +

> 

> But you do still need some sort of replay mechanism, right?  Not to

> replay the IOVA to PA mapping, but to call iommu_msi_set_aperture() for

> the new domain.  How will you know that this entry is an MSI reserved

> range or something else?  Perhaps we can't have a generic "reserved"

> type here.

Thanks for spotting this bug. I was not testing this case yet and
effectively I need to replay the set_aperture.

Thanks for the review

Best Regards

Eric

> 

>>  		while (iova < dma->iova + dma->size) {

>>  			phys_addr_t phys = iommu_iova_to_phys(d->domain, iova);

>>  			size_t size;

>

Patch

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 2d769d4..94a9916 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -391,7 +391,7 @@  static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
 	struct vfio_domain *domain, *d;
 	long unlocked = 0;
 
-	if (!dma->size)
+	if (!dma->size || dma->type != VFIO_IOVA_USER)
 		return;
 	/*
 	 * We use the IOMMU to track the physical addresses, otherwise we'd
@@ -727,6 +727,9 @@  static int vfio_iommu_replay(struct vfio_iommu *iommu,
 		dma = rb_entry(n, struct vfio_dma, node);
 		iova = dma->iova;
 
+		if (dma->type == VFIO_IOVA_RESERVED)
+			continue;
+
 		while (iova < dma->iova + dma->size) {
 			phys_addr_t phys = iommu_iova_to_phys(d->domain, iova);
 			size_t size;