Commit 3b8f7a24 authored by Brett Creeley's avatar Brett Creeley Committed by Alex Williamson
Browse files

vfio/pds: Only use a single SGL for both seq and ack 



Since the seq/ack operations never happen in parallel there
is no need for multiple scatter gather lists per region.
The current implementation is wasting memory. Fix this by
only using a single scatter-gather list for both the seq
and ack operations.

Signed-off-by: default avatarBrett Creeley <brett.creeley@amd.com>
Signed-off-by: default avatarShannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20231117001207.2793-3-brett.creeley@amd.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 4004497c

drivers/vfio/pci/pds/dirty.c

+25 −43
Original line number Diff line number Diff line
@@ -100,35 +100,35 @@ static void pds_vfio_dirty_free_bitmaps(struct pds_vfio_dirty *dirty) 
}



static void __pds_vfio_dirty_free_sgl(struct pds_vfio_pci_device *pds_vfio,

				      struct pds_vfio_bmp_info *bmp_info)

				      struct pds_vfio_dirty *dirty)

{

	struct pci_dev *pdev = pds_vfio->vfio_coredev.pdev;

	struct device *pdsc_dev = &pci_physfn(pdev)->dev;



	dma_unmap_single(pdsc_dev, bmp_info->sgl_addr,

			 bmp_info->num_sge * sizeof(struct pds_lm_sg_elem),

	dma_unmap_single(pdsc_dev, dirty->sgl_addr,

			 dirty->num_sge * sizeof(struct pds_lm_sg_elem),

			 DMA_BIDIRECTIONAL);

	kfree(bmp_info->sgl);

	kfree(dirty->sgl);



	bmp_info->num_sge = 0;

	bmp_info->sgl = NULL;

	bmp_info->sgl_addr = 0;

	dirty->num_sge = 0;

	dirty->sgl = NULL;

	dirty->sgl_addr = 0;

}



static void pds_vfio_dirty_free_sgl(struct pds_vfio_pci_device *pds_vfio)

{

	if (pds_vfio->dirty.host_seq.sgl)

		__pds_vfio_dirty_free_sgl(pds_vfio, &pds_vfio->dirty.host_seq);

	if (pds_vfio->dirty.host_ack.sgl)

		__pds_vfio_dirty_free_sgl(pds_vfio, &pds_vfio->dirty.host_ack);

	struct pds_vfio_dirty *dirty = &pds_vfio->dirty;



	if (dirty->sgl)

		__pds_vfio_dirty_free_sgl(pds_vfio, dirty);

}



static int __pds_vfio_dirty_alloc_sgl(struct pds_vfio_pci_device *pds_vfio,

				      struct pds_vfio_bmp_info *bmp_info,

static int pds_vfio_dirty_alloc_sgl(struct pds_vfio_pci_device *pds_vfio,

				    u32 page_count)

{

	struct pci_dev *pdev = pds_vfio->vfio_coredev.pdev;

	struct device *pdsc_dev = &pci_physfn(pdev)->dev;

	struct pds_vfio_dirty *dirty = &pds_vfio->dirty;

	struct pds_lm_sg_elem *sgl;

	dma_addr_t sgl_addr;

	size_t sgl_size;
@@ -147,30 +147,9 @@ static int __pds_vfio_dirty_alloc_sgl(struct pds_vfio_pci_device *pds_vfio, 
		return -EIO;

	}



	bmp_info->sgl = sgl;

	bmp_info->num_sge = max_sge;

	bmp_info->sgl_addr = sgl_addr;



	return 0;

}



static int pds_vfio_dirty_alloc_sgl(struct pds_vfio_pci_device *pds_vfio,

				    u32 page_count)

{

	struct pds_vfio_dirty *dirty = &pds_vfio->dirty;

	int err;



	err = __pds_vfio_dirty_alloc_sgl(pds_vfio, &dirty->host_seq,

					 page_count);

	if (err)

		return err;



	err = __pds_vfio_dirty_alloc_sgl(pds_vfio, &dirty->host_ack,

					 page_count);

	if (err) {

		__pds_vfio_dirty_free_sgl(pds_vfio, &dirty->host_seq);

		return err;

	}

	dirty->sgl = sgl;

	dirty->num_sge = max_sge;

	dirty->sgl_addr = sgl_addr;



	return 0;

}
@@ -328,6 +307,8 @@ static int pds_vfio_dirty_seq_ack(struct pds_vfio_pci_device *pds_vfio, 
	u8 dma_dir = read_seq ? DMA_FROM_DEVICE : DMA_TO_DEVICE;

	struct pci_dev *pdev = pds_vfio->vfio_coredev.pdev;

	struct device *pdsc_dev = &pci_physfn(pdev)->dev;

	struct pds_vfio_dirty *dirty = &pds_vfio->dirty;

	struct pds_lm_sg_elem *sgl;

	unsigned long long npages;

	struct sg_table sg_table;

	struct scatterlist *sg;
@@ -374,8 +355,9 @@ static int pds_vfio_dirty_seq_ack(struct pds_vfio_pci_device *pds_vfio, 
	if (err)

		goto out_free_sg_table;



	sgl = pds_vfio->dirty.sgl;

	for_each_sgtable_dma_sg(&sg_table, sg, i) {

		struct pds_lm_sg_elem *sg_elem = &bmp_info->sgl[i];

		struct pds_lm_sg_elem *sg_elem = &sgl[i];



		sg_elem->addr = cpu_to_le64(sg_dma_address(sg));

		sg_elem->len = cpu_to_le32(sg_dma_len(sg));
@@ -383,15 +365,15 @@ static int pds_vfio_dirty_seq_ack(struct pds_vfio_pci_device *pds_vfio, 


	num_sge = sg_table.nents;

	size = num_sge * sizeof(struct pds_lm_sg_elem);

	dma_sync_single_for_device(pdsc_dev, bmp_info->sgl_addr, size, dma_dir);

	err = pds_vfio_dirty_seq_ack_cmd(pds_vfio, bmp_info->sgl_addr, num_sge,

	dma_sync_single_for_device(pdsc_dev, dirty->sgl_addr, size, dma_dir);

	err = pds_vfio_dirty_seq_ack_cmd(pds_vfio, dirty->sgl_addr, num_sge,

					 offset, bmp_bytes, read_seq);

	if (err)

		dev_err(&pdev->dev,

			"Dirty bitmap %s failed offset %u bmp_bytes %u num_sge %u DMA 0x%llx: %pe\n",

			bmp_type_str, offset, bmp_bytes,

			num_sge, bmp_info->sgl_addr, ERR_PTR(err));

	dma_sync_single_for_cpu(pdsc_dev, bmp_info->sgl_addr, size, dma_dir);

			num_sge, dirty->sgl_addr, ERR_PTR(err));

	dma_sync_single_for_cpu(pdsc_dev, dirty->sgl_addr, size, dma_dir);



	dma_unmap_sgtable(pdsc_dev, &sg_table, dma_dir, 0);

out_free_sg_table:

drivers/vfio/pci/pds/dirty.h

+3 −3
Original line number Diff line number Diff line
@@ -7,9 +7,6 @@ 
struct pds_vfio_bmp_info {

	unsigned long *bmp;

	u32 bmp_bytes;

	struct pds_lm_sg_elem *sgl;

	dma_addr_t sgl_addr;

	u16 num_sge;

};



struct pds_vfio_dirty {
@@ -18,6 +15,9 @@ struct pds_vfio_dirty { 
	u64 region_size;

	u64 region_start;

	u64 region_page_size;

	struct pds_lm_sg_elem *sgl;

	dma_addr_t sgl_addr;

	u16 num_sge;

	bool is_enabled;

};