diff mbox series

[13/15] swiotlb: merge swiotlb-xen initialization into swiotlb

Message ID 20220314073129.1862284-14-hch@lst.de (mailing list archive)
State Superseded
Headers show
Series [01/15] dma-direct: use is_swiotlb_active in dma_direct_map_page | expand

Commit Message

Christoph Hellwig March 14, 2022, 7:31 a.m. UTC
Reuse the generic swiotlb initialization for xen-swiotlb.  For ARM/ARM64
this works trivially, while for x86 xen_swiotlb_fixup needs to be passed
as the remap argument to swiotlb_init_remap/swiotlb_init_late.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arm/xen/mm.c               |  21 +++---
 arch/x86/include/asm/xen/page.h |   5 --
 arch/x86/kernel/pci-dma.c       |  19 +++--
 drivers/xen/swiotlb-xen.c       | 128 +-------------------------------
 include/xen/arm/page.h          |   1 -
 include/xen/swiotlb-xen.h       |   8 +-
 6 files changed, 27 insertions(+), 155 deletions(-)

Comments

Boris Ostrovsky March 14, 2022, 11:07 p.m. UTC | #1
On 3/14/22 3:31 AM, Christoph Hellwig wrote:
> -
>   static void __init pci_xen_swiotlb_init(void)
>   {
>   	if (!xen_initial_domain() && !x86_swiotlb_enable)
>   		return;
>   	x86_swiotlb_enable = true;
> -	xen_swiotlb = true;
> -	xen_swiotlb_init_early();
> +	swiotlb_init_remap(true, x86_swiotlb_flags, xen_swiotlb_fixup);


I think we need to have SWIOTLB_ANY set in x86_swiotlb_flags here.



>   	dma_ops = &xen_swiotlb_dma_ops;
>   	if (IS_ENABLED(CONFIG_PCI))
>   		pci_request_acs();
> @@ -88,14 +85,16 @@ static void __init pci_xen_swiotlb_init(void)
>   
>   int pci_xen_swiotlb_init_late(void)
>   {
> -	int rc;
> -
> -	if (xen_swiotlb)
> +	if (dma_ops == &xen_swiotlb_dma_ops)
>   		return 0;
>   
> -	rc = xen_swiotlb_init();
> -	if (rc)
> -		return rc;
> +	/* we can work with the default swiotlb */
> +	if (!io_tlb_default_mem.nslabs) {
> +		int rc = swiotlb_init_late(swiotlb_size_or_default(),
> +					   GFP_KERNEL, xen_swiotlb_fixup);


This may be comment for previous patch but looking at swiotlb_init_late():


retry:
         order = get_order(nslabs << IO_TLB_SHIFT);
         nslabs = SLABS_PER_PAGE << order;
         bytes = nslabs << IO_TLB_SHIFT;

         while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
                 vstart = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN,
                                                   order);
                 if (vstart)
                         break;
                 order--;
         }

         if (!vstart)
                 return -ENOMEM;
         if (remap)
                 rc = remap(vstart, nslabs);
         if (rc) {
                 free_pages((unsigned long)vstart, order);

                 /* Min is 2MB */
                 if (nslabs <= 1024)
                         return rc;
                 nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
                 goto retry;
         }

         if (order != get_order(bytes)) {
                 pr_warn("only able to allocate %ld MB\n",
                         (PAGE_SIZE << order) >> 20);
                 nslabs = SLABS_PER_PAGE << order; <=======
         }

         rc = swiotlb_late_init_with_tbl(vstart, nslabs);

Notice that we don't do remap() after final update to nslabs. We should.



-boris
Stefano Stabellini March 15, 2022, midnight UTC | #2
On Mon, 14 Mar 2022, Christoph Hellwig wrote:
> Reuse the generic swiotlb initialization for xen-swiotlb.  For ARM/ARM64
> this works trivially, while for x86 xen_swiotlb_fixup needs to be passed
> as the remap argument to swiotlb_init_remap/swiotlb_init_late.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

For arch/arm/xen and drivers/xen/swiotlb-xen.c

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Christoph Hellwig March 15, 2022, 6:48 a.m. UTC | #3
On Mon, Mar 14, 2022 at 07:07:44PM -0400, Boris Ostrovsky wrote:
>> +	swiotlb_init_remap(true, x86_swiotlb_flags, xen_swiotlb_fixup);
>
>
> I think we need to have SWIOTLB_ANY set in x86_swiotlb_flags here.

Yes.

> Notice that we don't do remap() after final update to nslabs. We should.

Indeed.  I've pushed the fixed patches to the git tree and attached
the patches 12, 13 and 14 in case that is easier:
diff mbox series

Patch

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 28c2070602535..ff05a7899cb86 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -23,22 +23,20 @@ 
 #include <asm/xen/hypercall.h>
 #include <asm/xen/interface.h>
 
-unsigned long xen_get_swiotlb_free_pages(unsigned int order)
+static gfp_t xen_swiotlb_gfp(void)
 {
 	phys_addr_t base;
-	gfp_t flags = __GFP_NOWARN|__GFP_KSWAPD_RECLAIM;
 	u64 i;
 
 	for_each_mem_range(i, &base, NULL) {
 		if (base < (phys_addr_t)0xffffffff) {
 			if (IS_ENABLED(CONFIG_ZONE_DMA32))
-				flags |= __GFP_DMA32;
-			else
-				flags |= __GFP_DMA;
-			break;
+				return __GFP_DMA32;
+			return __GFP_DMA;
 		}
 	}
-	return __get_free_pages(flags, order);
+
+	return GFP_KERNEL;
 }
 
 static bool hypercall_cflush = false;
@@ -140,10 +138,13 @@  static int __init xen_mm_init(void)
 	if (!xen_swiotlb_detect())
 		return 0;
 
-	rc = xen_swiotlb_init();
 	/* we can work with the default swiotlb */
-	if (rc < 0 && rc != -EEXIST)
-		return rc;
+	if (!io_tlb_default_mem.nslabs) {
+		rc = swiotlb_init_late(swiotlb_size_or_default(),
+				       xen_swiotlb_gfp(), NULL);
+		if (rc < 0)
+			return rc;
+	}
 
 	cflush.op = 0;
 	cflush.a.dev_bus_addr = 0;
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index e989bc2269f54..1fc67df500145 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -357,9 +357,4 @@  static inline bool xen_arch_need_swiotlb(struct device *dev,
 	return false;
 }
 
-static inline unsigned long xen_get_swiotlb_free_pages(unsigned int order)
-{
-	return __get_free_pages(__GFP_NOWARN, order);
-}
-
 #endif /* _ASM_X86_XEN_PAGE_H */
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index a705a199bf8a3..dbb7b83fc3e48 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -72,15 +72,12 @@  static inline void __init pci_swiotlb_detect(void)
 #endif /* CONFIG_SWIOTLB */
 
 #ifdef CONFIG_SWIOTLB_XEN
-static bool xen_swiotlb;
-
 static void __init pci_xen_swiotlb_init(void)
 {
 	if (!xen_initial_domain() && !x86_swiotlb_enable)
 		return;
 	x86_swiotlb_enable = true;
-	xen_swiotlb = true;
-	xen_swiotlb_init_early();
+	swiotlb_init_remap(true, x86_swiotlb_flags, xen_swiotlb_fixup);
 	dma_ops = &xen_swiotlb_dma_ops;
 	if (IS_ENABLED(CONFIG_PCI))
 		pci_request_acs();
@@ -88,14 +85,16 @@  static void __init pci_xen_swiotlb_init(void)
 
 int pci_xen_swiotlb_init_late(void)
 {
-	int rc;
-
-	if (xen_swiotlb)
+	if (dma_ops == &xen_swiotlb_dma_ops)
 		return 0;
 
-	rc = xen_swiotlb_init();
-	if (rc)
-		return rc;
+	/* we can work with the default swiotlb */
+	if (!io_tlb_default_mem.nslabs) {
+		int rc = swiotlb_init_late(swiotlb_size_or_default(),
+					   GFP_KERNEL, xen_swiotlb_fixup);
+		if (rc < 0)
+			return rc;
+	}
 
 	/* XXX: this switches the dma ops under live devices! */
 	dma_ops = &xen_swiotlb_dma_ops;
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index c2da3eb4826e8..df8085b50df10 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -104,7 +104,7 @@  static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
 	return 0;
 }
 
-static int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
+int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
 {
 	int rc;
 	unsigned int order = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT);
@@ -130,132 +130,6 @@  static int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
 	return 0;
 }
 
-enum xen_swiotlb_err {
-	XEN_SWIOTLB_UNKNOWN = 0,
-	XEN_SWIOTLB_ENOMEM,
-	XEN_SWIOTLB_EFIXUP
-};
-
-static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
-{
-	switch (err) {
-	case XEN_SWIOTLB_ENOMEM:
-		return "Cannot allocate Xen-SWIOTLB buffer\n";
-	case XEN_SWIOTLB_EFIXUP:
-		return "Failed to get contiguous memory for DMA from Xen!\n"\
-		    "You either: don't have the permissions, do not have"\
-		    " enough free memory under 4GB, or the hypervisor memory"\
-		    " is too fragmented!";
-	default:
-		break;
-	}
-	return "";
-}
-
-int xen_swiotlb_init(void)
-{
-	enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
-	unsigned long bytes = swiotlb_size_or_default();
-	unsigned long nslabs = bytes >> IO_TLB_SHIFT;
-	unsigned int order, repeat = 3;
-	int rc = -ENOMEM;
-	char *start;
-
-	if (io_tlb_default_mem.nslabs) {
-		pr_warn("swiotlb buffer already initialized\n");
-		return -EEXIST;
-	}
-
-retry:
-	m_ret = XEN_SWIOTLB_ENOMEM;
-	order = get_order(bytes);
-
-	/*
-	 * Get IO TLB memory from any location.
-	 */
-#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
-#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
-	while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
-		start = (void *)xen_get_swiotlb_free_pages(order);
-		if (start)
-			break;
-		order--;
-	}
-	if (!start)
-		goto exit;
-	if (order != get_order(bytes)) {
-		pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
-			(PAGE_SIZE << order) >> 20);
-		nslabs = SLABS_PER_PAGE << order;
-		bytes = nslabs << IO_TLB_SHIFT;
-	}
-
-	/*
-	 * And replace that memory with pages under 4GB.
-	 */
-	rc = xen_swiotlb_fixup(start, nslabs);
-	if (rc) {
-		free_pages((unsigned long)start, order);
-		m_ret = XEN_SWIOTLB_EFIXUP;
-		goto error;
-	}
-	rc = swiotlb_late_init_with_tbl(start, nslabs);
-	if (rc)
-		return rc;
-	return 0;
-error:
-	if (nslabs > 1024 && repeat--) {
-		/* Min is 2MB */
-		nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
-		bytes = nslabs << IO_TLB_SHIFT;
-		pr_info("Lowering to %luMB\n", bytes >> 20);
-		goto retry;
-	}
-exit:
-	pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
-	return rc;
-}
-
-#ifdef CONFIG_X86
-void __init xen_swiotlb_init_early(void)
-{
-	unsigned long bytes = swiotlb_size_or_default();
-	unsigned long nslabs = bytes >> IO_TLB_SHIFT;
-	unsigned int repeat = 3;
-	char *start;
-	int rc;
-
-retry:
-	/*
-	 * Get IO TLB memory from any location.
-	 */
-	start = memblock_alloc(PAGE_ALIGN(bytes),
-			       IO_TLB_SEGSIZE << IO_TLB_SHIFT);
-	if (!start)
-		panic("%s: Failed to allocate %lu bytes\n",
-		      __func__, PAGE_ALIGN(bytes));
-
-	/*
-	 * And replace that memory with pages under 4GB.
-	 */
-	rc = xen_swiotlb_fixup(start, nslabs);
-	if (rc) {
-		memblock_free(start, PAGE_ALIGN(bytes));
-		if (nslabs > 1024 && repeat--) {
-			/* Min is 2MB */
-			nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
-			bytes = nslabs << IO_TLB_SHIFT;
-			pr_info("Lowering to %luMB\n", bytes >> 20);
-			goto retry;
-		}
-		panic("%s (rc:%d)", xen_swiotlb_error(XEN_SWIOTLB_EFIXUP), rc);
-	}
-
-	if (swiotlb_init_with_tbl(start, nslabs, SWIOTLB_VERBOSE))
-		panic("Cannot allocate SWIOTLB buffer");
-}
-#endif /* CONFIG_X86 */
-
 static void *
 xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 			   dma_addr_t *dma_handle, gfp_t flags,
diff --git a/include/xen/arm/page.h b/include/xen/arm/page.h
index ac1b654705631..7e199c6656b90 100644
--- a/include/xen/arm/page.h
+++ b/include/xen/arm/page.h
@@ -115,6 +115,5 @@  static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 bool xen_arch_need_swiotlb(struct device *dev,
 			   phys_addr_t phys,
 			   dma_addr_t dev_addr);
-unsigned long xen_get_swiotlb_free_pages(unsigned int order);
 
 #endif /* _ASM_ARM_XEN_PAGE_H */
diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
index b3e647f86e3e2..590ceb923f0c8 100644
--- a/include/xen/swiotlb-xen.h
+++ b/include/xen/swiotlb-xen.h
@@ -10,8 +10,12 @@  void xen_dma_sync_for_cpu(struct device *dev, dma_addr_t handle,
 void xen_dma_sync_for_device(struct device *dev, dma_addr_t handle,
 			     size_t size, enum dma_data_direction dir);
 
-int xen_swiotlb_init(void);
-void __init xen_swiotlb_init_early(void);
+#ifdef CONFIG_SWIOTLB_XEN
+int xen_swiotlb_fixup(void *buf, unsigned long nslabs);
+#else
+#define xen_swiotlb_fixup NULL
+#endif
+
 extern const struct dma_map_ops xen_swiotlb_dma_ops;
 
 #endif /* __LINUX_SWIOTLB_XEN_H */