dma: use per-device dma_arenas for dedicated devices

This commit adds the plumbing for picking a dma_arena for a device,
instead of assuming the default physical pages arena.

Future commits will add the ability to create and set a process's
user_pages arena.

Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>

kern/include/dma.h

diff --git a/kern/include/dma.h b/kern/include/dma.h
index 8343dec..6ed7db6 100644
--- a/kern/include/dma.h
+++ b/kern/include/dma.h
@@ -9,6 +9,7 @@
 #pragma once
 
 #include <arena.h>
+#include <arch/pci.h>
 
 typedef physaddr_t dma_addr_t;
 
@@ -20,6 +21,7 @@
 
 /* Default arena: basically just physical pages */
 extern struct dma_arena dma_phys_pages;
+struct dma_arena *dev_to_dma_arena(struct device *d);
 
 void dma_arena_init(void);
 
@@ -31,7 +33,7 @@
 		    size_t size);
 
 /* Compatible with Linux's DMA pool */
-struct dma_pool *dma_pool_create(const char *name, void *dev,
+struct dma_pool *dma_pool_create(const char *name, struct device *dev,
 				 size_t size, size_t align, size_t allocation);
 void dma_pool_destroy(struct dma_pool *pool);
 void *dma_pool_alloc(struct dma_pool *pool, int mem_flags, dma_addr_t *handle);

kern/include/env.h

diff --git a/kern/include/env.h b/kern/include/env.h
index dba5378..3689106 100644
--- a/kern/include/env.h
+++ b/kern/include/env.h
@@ -22,6 +22,7 @@
 #include <ns.h>
 #include <arch/vmm/vmm.h>
 #include <arch/pci.h>
+#include <dma.h>
 
 TAILQ_HEAD(vcore_tailq, vcore);
 /* 'struct proc_list' declared in sched.h (not ideal...) */
@@ -121,6 +122,7 @@
 	struct strace		*strace;
 	struct pcidev_tq	pci_devices; /* for device passthru */
 	TAILQ_ENTRY(proc)	iommu_link;
+	struct dma_arena	*user_pages;
 };
 
 /* Til we remove all Env references */

kern/include/linux_compat.h

diff --git a/kern/include/linux_compat.h b/kern/include/linux_compat.h
index bc92122..b331334 100644
--- a/kern/include/linux_compat.h
+++ b/kern/include/linux_compat.h
@@ -126,19 +126,19 @@
 static inline void *dma_alloc_coherent(struct device *dev, size_t size,
 				       dma_addr_t *dma_handle, int gfp)
 {
-	return dma_arena_zalloc(&dma_phys_pages, size, dma_handle, gfp);
+	return dma_arena_zalloc(dev_to_dma_arena(dev), size, dma_handle, gfp);
 }
 
 static inline void *dma_zalloc_coherent(struct device *dev, size_t size,
 					dma_addr_t *dma_handle, int gfp)
 {
-	return dma_arena_zalloc(&dma_phys_pages, size, dma_handle, gfp);
+	return dma_arena_zalloc(dev_to_dma_arena(dev), size, dma_handle, gfp);
 }
 
 static inline void dma_free_coherent(struct device *dev, size_t size,
 				     void *cpu_addr, dma_addr_t dma_handle)
 {
-	dma_arena_free(&dma_phys_pages, cpu_addr, dma_handle, size);
+	dma_arena_free(dev_to_dma_arena(dev), cpu_addr, dma_handle, size);
 }
 
 #define dma_map_single(dev, addr, size, direction)                             \

kern/src/dma.c

diff --git a/kern/src/dma.c b/kern/src/dma.c
index fcad42d..f4293e4 100644
--- a/kern/src/dma.c
+++ b/kern/src/dma.c
@@ -54,6 +54,23 @@
  * xalloc, and maybe more flexibility. */
 struct dma_arena dma_phys_pages;
 
+struct dma_arena *dev_to_dma_arena(struct device *d)
+{
+	struct pci_device *pdev;
+
+	if (!d)
+		return &dma_phys_pages;
+	pdev = container_of(d, struct pci_device, linux_dev);
+	if (!pdev->proc_owner)
+		return &dma_phys_pages;
+	if (!pdev->proc_owner->user_pages) {
+		warn("Proc %d owns a device, but has no user_pages!",
+		     pdev->proc_owner->pid);
+		return &dma_phys_pages;
+	}
+	return pdev->proc_owner->user_pages;
+}
+
 static void *dma_phys_a(struct arena *a, size_t amt, int flags)
 {
 	return (void*)PADDR(arena_alloc(a, amt, flags));
@@ -147,7 +164,7 @@
 	struct dma_arena	*source;
 };
 
-struct dma_pool *dma_pool_create(const char *name, void *dev,
+struct dma_pool *dma_pool_create(const char *name, struct device *dev,
 				 size_t size, size_t align, size_t boundary)
 {
 	struct dma_pool *dp;
@@ -164,8 +181,7 @@
 		align = size;
 	}
 	dp = kzmalloc(sizeof(struct dma_pool), MEM_WAIT);
-	/* TODO: this will be device specific.  Assuming the default. */
-	dp->source = &dma_phys_pages;
+	dp->source = dev_to_dma_arena(dev);
 	/* We're sourcing directly from the dma_arena's arena. */
 	__kmem_cache_create(&dp->kc, name, size, align, KMC_NOTOUCH,
 			    &dp->source->arena, NULL, NULL, NULL);