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PCI: hv: Reserve hv_pci swiotlb from buddy and publish via sysfs #260

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PCI: hv: Reserve hv_pci swiotlb from buddy and publish via sysfs #260

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133 changes: 115 additions & 18 deletions drivers/pci/controller/pci-hyperv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -472,15 +472,20 @@ static int pci_ring_size = VMBUS_RING_SIZE(SZ_16K);

static phys_addr_t hv_pci_swiotlb_base;
static size_t hv_pci_swiotlb_size;
static struct page *hv_pci_swiotlb_pages;
static unsigned long hv_pci_swiotlb_nr_pages;

/* Parse hv_pci_swiotlb=<size>; the base is picked at core_initcall time. */
static int __init early_hv_pci_swiotlb(char *p)
{
hv_pci_swiotlb_base = memparse(p, &p);
if (*p == ',')
hv_pci_swiotlb_size = memparse(p + 1, NULL);
if (hv_pci_swiotlb_base && hv_pci_swiotlb_size)
memblock_reserve(hv_pci_swiotlb_base, hv_pci_swiotlb_size);
return 0;
if (!p || !*p)
return 0;

hv_pci_swiotlb_size = memparse(p, NULL);
if (hv_pci_swiotlb_size)
hv_pci_swiotlb_size = ALIGN(hv_pci_swiotlb_size, SZ_2M);

return 0;
}
Comment on lines 479 to 489
Comment on lines 479 to 489
early_param("hv_pci_swiotlb", early_hv_pci_swiotlb);

Expand Down Expand Up @@ -4241,10 +4246,44 @@ static struct hv_driver hv_pci_drv = {
.resume = hv_pci_resume,
};

/* Publish swiotlb_{base,size} so userspace can forward the GPA to the host. */
static ssize_t swiotlb_base_show(struct device_driver *drv, char *buf)
{
return sysfs_emit(buf, "0x%llx\n",
(unsigned long long)hv_pci_swiotlb_base);
}
static DRIVER_ATTR_RO(swiotlb_base);

static ssize_t swiotlb_size_show(struct device_driver *drv, char *buf)
{
return sysfs_emit(buf, "%zu\n", hv_pci_swiotlb_size);
}
static DRIVER_ATTR_RO(swiotlb_size);

static void hv_pci_swiotlb_unpublish(void)
{
driver_remove_file(&hv_pci_drv.driver, &driver_attr_swiotlb_size);
driver_remove_file(&hv_pci_drv.driver, &driver_attr_swiotlb_base);
}

static void hv_pci_swiotlb_publish(void)
{
if (driver_create_file(&hv_pci_drv.driver, &driver_attr_swiotlb_base) ||
driver_create_file(&hv_pci_drv.driver, &driver_attr_swiotlb_size)) {
pr_warn("hv_pci: failed to publish swiotlb range to sysfs\n");
hv_pci_swiotlb_unpublish();
}
}

static void __exit exit_hv_pci_drv(void)
{
if (hv_pci_swiotlb_pool)
Comment on lines +4263 to +4280
hv_pci_swiotlb_unpublish();

vmbus_driver_unregister(&hv_pci_drv);

/* No swiotlb_destroy_pool() exists, so hv_pci_swiotlb_pages is leaked. */

hvpci_block_ops.read_block = NULL;
hvpci_block_ops.write_block = NULL;
hvpci_block_ops.reg_blk_invalidate = NULL;
Expand All @@ -4260,17 +4299,6 @@ static int __init init_hv_pci_drv(void)
if (hv_root_partition() && !hv_nested)
return -ENODEV;

if (hv_pci_swiotlb_base && hv_pci_swiotlb_size) {
hv_pci_swiotlb_pool = swiotlb_create_pool(hv_pci_swiotlb_base,
hv_pci_swiotlb_size,
"hv-pci-swiotlb");
if (IS_ERR(hv_pci_swiotlb_pool)) {
pr_err("hv_pci: failed to create swiotlb pool: %ld\n",
PTR_ERR(hv_pci_swiotlb_pool));
hv_pci_swiotlb_pool = NULL;
}
}

ret = hv_pci_irqchip_init();
if (ret)
return ret;
Expand All @@ -4283,9 +4311,78 @@ static int __init init_hv_pci_drv(void)
hvpci_block_ops.write_block = hv_write_config_block;
hvpci_block_ops.reg_blk_invalidate = hv_register_block_invalidate;

return vmbus_driver_register(&hv_pci_drv);
ret = vmbus_driver_register(&hv_pci_drv);
if (ret)
return ret;

if (hv_pci_swiotlb_pool)
hv_pci_swiotlb_publish();

return 0;
}

#ifdef CONFIG_CONTIG_ALLOC
/*
* Reserve the hv_pci swiotlb pool from the buddy allocator. __GFP_DMA32
* keeps the range below 4 GiB; kernel ownership keeps Hyper-V page
* reporting from yanking the backing. Gated on CONFIG_CONTIG_ALLOC.
*/
static int __init hv_pci_swiotlb_alloc_pool(void)
{
phys_addr_t end;
unsigned long nr_pages;
struct page *pages;

if (!hv_pci_swiotlb_size)
return 0;

nr_pages = hv_pci_swiotlb_size >> PAGE_SHIFT;

/* UMA on WSL; first_online_node biases nothing in practice. */
pages = alloc_contig_pages(nr_pages,
GFP_KERNEL | __GFP_DMA32 | __GFP_ZERO,
first_online_node, &node_online_map);
if (!pages) {
pr_warn("hv_pci: failed to allocate %zu-byte swiotlb pool below 4G; feature disabled\n",
hv_pci_swiotlb_size);
hv_pci_swiotlb_size = 0;
return 0;
}

hv_pci_swiotlb_pages = pages;
hv_pci_swiotlb_nr_pages = nr_pages;
Comment on lines +4352 to +4353
hv_pci_swiotlb_base = page_to_phys(pages);
end = hv_pci_swiotlb_base + hv_pci_swiotlb_size;

pr_info("hv_pci: reserved swiotlb pool [%pa..%pa)\n",
&hv_pci_swiotlb_base, &end);

hv_pci_swiotlb_pool = swiotlb_create_pool(hv_pci_swiotlb_base,
hv_pci_swiotlb_size,
"hv-pci-swiotlb");
if (IS_ERR(hv_pci_swiotlb_pool)) {
pr_err("hv_pci: failed to create swiotlb pool: %ld\n",
PTR_ERR(hv_pci_swiotlb_pool));
hv_pci_swiotlb_pool = NULL;
free_contig_range(page_to_pfn(pages), nr_pages);
hv_pci_swiotlb_pages = NULL;
hv_pci_swiotlb_nr_pages = 0;
hv_pci_swiotlb_base = 0;
hv_pci_swiotlb_size = 0;
}

return 0;
}
#else
static int __init hv_pci_swiotlb_alloc_pool(void)
{
if (hv_pci_swiotlb_size)
pr_warn("hv_pci: CONFIG_CONTIG_ALLOC disabled; hv_pci_swiotlb= ignored\n");
return 0;
}
#endif
core_initcall(hv_pci_swiotlb_alloc_pool);

module_init(init_hv_pci_drv);
module_exit(exit_hv_pci_drv);

Expand Down