VMCI: Add support for virtual IOMMU

This patch adds support for virtual IOMMU to the vmci module.  We switch
to DMA consistent mappings for guest queuepair and doorbell pages that
are passed to the device.  We still allocate each page individually,
since there's no guarantee that we'll get a contiguous block of physical
for an entire queuepair (especially since we allow up to 128 MiB!).

Also made the split between guest and host in the kernelIf struct much
clearer.  Now it's obvious which fields are which.

Acked-by: George Zhang <georgezhang@vmware.com>
Acked-by: Aditya Sarwade <asarwade@vmware.com>
Signed-off-by: Andy King <acking@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 104 insertions, 76 deletions

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index 8698e0c5bdb4..a0515a6d6ebd 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -21,6 +21,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/pagemap.h>
+#include <linux/pci.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/uio.h>
@@ -146,12 +147,20 @@ typedef int vmci_memcpy_from_queue_func(void *dest, size_t dest_offset,
 
 /* The Kernel specific component of the struct vmci_queue structure. */
 struct vmci_queue_kern_if {
-	struct page **page;
-	struct page **header_page;
 	struct mutex __mutex;	/* Protects the queue. */
 	struct mutex *mutex;	/* Shared by producer and consumer queues. */
-	bool host;
-	size_t num_pages;
+	size_t num_pages;	/* Number of pages incl. header. */
+	bool host;		/* Host or guest? */
+	union {
+		struct {
+			dma_addr_t *pas;
+			void **vas;
+		} g;		/* Used by the guest. */
+		struct {
+			struct page **page;
+			struct page **header_page;
+		} h;		/* Used by the host. */
+	} u;
 };
 
 /*
@@ -263,59 +272,65 @@ static void qp_free_queue(void *q, u64 size)
 	struct vmci_queue *queue = q;
 
 	if (queue) {
-		u64 i = DIV_ROUND_UP(size, PAGE_SIZE);
+		u64 i;
 
-		while (i)
-			__free_page(queue->kernel_if->page[--i]);
+		/* Given size does not include header, so add in a page here. */
+		for (i = 0; i < DIV_ROUND_UP(size, PAGE_SIZE) + 1; i++) {
+			dma_free_coherent(&vmci_pdev->dev, PAGE_SIZE,
+					  queue->kernel_if->u.g.vas[i],
+					  queue->kernel_if->u.g.pas[i]);
+		}
 
-		vfree(queue->q_header);
+		vfree(queue);
 	}
 }
 
 /*
- * Allocates kernel VA space of specified size, plus space for the
- * queue structure/kernel interface and the queue header.  Allocates
- * physical pages for the queue data pages.
- *
- * PAGE m:      struct vmci_queue_header (struct vmci_queue->q_header)
- * PAGE m+1:    struct vmci_queue
- * PAGE m+1+q:  struct vmci_queue_kern_if (struct vmci_queue->kernel_if)
- * PAGE n-size: Data pages (struct vmci_queue->kernel_if->page[])
+ * Allocates kernel queue pages of specified size with IOMMU mappings,
+ * plus space for the queue structure/kernel interface and the queue
+ * header.
  */
 static void *qp_alloc_queue(u64 size, u32 flags)
 {
 	u64 i;
 	struct vmci_queue *queue;
-	struct vmci_queue_header *q_header;
-	const u64 num_data_pages = DIV_ROUND_UP(size, PAGE_SIZE);
-	const uint queue_size =
-	    PAGE_SIZE +
-	    sizeof(*queue) + sizeof(*(queue->kernel_if)) +
-	    num_data_pages * sizeof(*(queue->kernel_if->page));
-
-	q_header = vmalloc(queue_size);
-	if (!q_header)
+	const size_t num_pages = DIV_ROUND_UP(size, PAGE_SIZE) + 1;
+	const size_t pas_size = num_pages * sizeof(*queue->kernel_if->u.g.pas);
+	const size_t vas_size = num_pages * sizeof(*queue->kernel_if->u.g.vas);
+	const size_t queue_size =
+		sizeof(*queue) + sizeof(*queue->kernel_if) +
+		pas_size + vas_size;
+
+	queue = vmalloc(queue_size);
+	if (!queue)
 		return NULL;
 
-	queue = (void *)q_header + PAGE_SIZE;
-	queue->q_header = q_header;
+	queue->q_header = NULL;
 	queue->saved_header = NULL;
 	queue->kernel_if = (struct vmci_queue_kern_if *)(queue + 1);
-	queue->kernel_if->header_page = NULL;	/* Unused in guest. */
-	queue->kernel_if->page = (struct page **)(queue->kernel_if + 1);
+	queue->kernel_if->mutex = NULL;
+	queue->kernel_if->num_pages = num_pages;
+	queue->kernel_if->u.g.pas = (dma_addr_t *)(queue->kernel_if + 1);
+	queue->kernel_if->u.g.vas =
+		(void **)((u8 *)queue->kernel_if->u.g.pas + pas_size);
 	queue->kernel_if->host = false;
 
-	for (i = 0; i < num_data_pages; i++) {
-		queue->kernel_if->page[i] = alloc_pages(GFP_KERNEL, 0);
-		if (!queue->kernel_if->page[i])
-			goto fail;
+	for (i = 0; i < num_pages; i++) {
+		queue->kernel_if->u.g.vas[i] =
+			dma_alloc_coherent(&vmci_pdev->dev, PAGE_SIZE,
+					   &queue->kernel_if->u.g.pas[i],
+					   GFP_KERNEL);
+		if (!queue->kernel_if->u.g.vas[i]) {
+			/* Size excl. the header. */
+			qp_free_queue(queue, i * PAGE_SIZE);
+			return NULL;
+		}
 	}
 
-	return (void *)queue;
+	/* Queue header is the first page. */
+	queue->q_header = queue->kernel_if->u.g.vas[0];
 
- fail:
-	qp_free_queue(queue, i * PAGE_SIZE);
-	return NULL;
+	return queue;
 }
 
 /*
@@ -334,13 +349,18 @@ static int __qp_memcpy_to_queue(struct vmci_queue *queue,
 	size_t bytes_copied = 0;
 
 	while (bytes_copied < size) {
-		u64 page_index = (queue_offset + bytes_copied) / PAGE_SIZE;
-		size_t page_offset =
+		const u64 page_index =
+			(queue_offset + bytes_copied) / PAGE_SIZE;
+		const size_t page_offset =
 		    (queue_offset + bytes_copied) & (PAGE_SIZE - 1);
 		void *va;
 		size_t to_copy;
 
-		va = kmap(kernel_if->page[page_index]);
+		if (kernel_if->host)
+			va = kmap(kernel_if->u.h.page[page_index]);
+		else
+			va = kernel_if->u.g.vas[page_index + 1];
+			/* Skip header. */
 
 		if (size - bytes_copied > PAGE_SIZE - page_offset)
 			/* Enough payload to fill up from this page. */
@@ -356,7 +376,8 @@ static int __qp_memcpy_to_queue(struct vmci_queue *queue,
 			err = memcpy_fromiovec((u8 *)va + page_offset,
 					       iov, to_copy);
 			if (err != 0) {
-				kunmap(kernel_if->page[page_index]);
+				if (kernel_if->host)
+					kunmap(kernel_if->u.h.page[page_index]);
 				return VMCI_ERROR_INVALID_ARGS;
 			}
 		} else {
@@ -365,7 +386,8 @@ static int __qp_memcpy_to_queue(struct vmci_queue *queue,
 		}
 
 		bytes_copied += to_copy;
-		kunmap(kernel_if->page[page_index]);
+		if (kernel_if->host)
+			kunmap(kernel_if->u.h.page[page_index]);
 	}
 
 	return VMCI_SUCCESS;
@@ -387,13 +409,18 @@ static int __qp_memcpy_from_queue(void *dest,
 	size_t bytes_copied = 0;
 
 	while (bytes_copied < size) {
-		u64 page_index = (queue_offset + bytes_copied) / PAGE_SIZE;
-		size_t page_offset =
+		const u64 page_index =
+			(queue_offset + bytes_copied) / PAGE_SIZE;
+		const size_t page_offset =
 		    (queue_offset + bytes_copied) & (PAGE_SIZE - 1);
 		void *va;
 		size_t to_copy;
 
-		va = kmap(kernel_if->page[page_index]);
+		if (kernel_if->host)
+			va = kmap(kernel_if->u.h.page[page_index]);
+		else
+			va = kernel_if->u.g.vas[page_index + 1];
+			/* Skip header. */
 
 		if (size - bytes_copied > PAGE_SIZE - page_offset)
 			/* Enough payload to fill up this page. */
@@ -409,7 +436,8 @@ static int __qp_memcpy_from_queue(void *dest,
 			err = memcpy_toiovec(iov, (u8 *)va + page_offset,
 					     to_copy);
 			if (err != 0) {
-				kunmap(kernel_if->page[page_index]);
+				if (kernel_if->host)
+					kunmap(kernel_if->u.h.page[page_index]);
 				return VMCI_ERROR_INVALID_ARGS;
 			}
 		} else {
@@ -418,7 +446,8 @@ static int __qp_memcpy_from_queue(void *dest,
 		}
 
 		bytes_copied += to_copy;
-		kunmap(kernel_if->page[page_index]);
+		if (kernel_if->host)
+			kunmap(kernel_if->u.h.page[page_index]);
 	}
 
 	return VMCI_SUCCESS;
@@ -460,12 +489,11 @@ static int qp_alloc_ppn_set(void *prod_q,
 		return VMCI_ERROR_NO_MEM;
 	}
 
-	produce_ppns[0] = page_to_pfn(vmalloc_to_page(produce_q->q_header));
-	for (i = 1; i < num_produce_pages; i++) {
+	for (i = 0; i < num_produce_pages; i++) {
 		unsigned long pfn;
 
 		produce_ppns[i] =
-		    page_to_pfn(produce_q->kernel_if->page[i - 1]);
+			produce_q->kernel_if->u.g.pas[i] >> PAGE_SHIFT;
 		pfn = produce_ppns[i];
 
 		/* Fail allocation if PFN isn't supported by hypervisor. */
@@ -474,12 +502,11 @@ static int qp_alloc_ppn_set(void *prod_q,
 			goto ppn_error;
 	}
 
-	consume_ppns[0] = page_to_pfn(vmalloc_to_page(consume_q->q_header));
-	for (i = 1; i < num_consume_pages; i++) {
+	for (i = 0; i < num_consume_pages; i++) {
 		unsigned long pfn;
 
 		consume_ppns[i] =
-		    page_to_pfn(consume_q->kernel_if->page[i - 1]);
+			consume_q->kernel_if->u.g.pas[i] >> PAGE_SHIFT;
 		pfn = consume_ppns[i];
 
 		/* Fail allocation if PFN isn't supported by hypervisor. */
@@ -590,21 +617,20 @@ static struct vmci_queue *qp_host_alloc_queue(u64 size)
 	const size_t num_pages = DIV_ROUND_UP(size, PAGE_SIZE) + 1;
 	const size_t queue_size = sizeof(*queue) + sizeof(*(queue->kernel_if));
 	const size_t queue_page_size =
-	    num_pages * sizeof(*queue->kernel_if->page);
+	    num_pages * sizeof(*queue->kernel_if->u.h.page);
 
 	queue = kzalloc(queue_size + queue_page_size, GFP_KERNEL);
 	if (queue) {
 		queue->q_header = NULL;
 		queue->saved_header = NULL;
-		queue->kernel_if =
-		    (struct vmci_queue_kern_if *)((u8 *)queue +
-						  sizeof(*queue));
+		queue->kernel_if = (struct vmci_queue_kern_if *)(queue + 1);
 		queue->kernel_if->host = true;
 		queue->kernel_if->mutex = NULL;
 		queue->kernel_if->num_pages = num_pages;
-		queue->kernel_if->header_page =
+		queue->kernel_if->u.h.header_page =
 		    (struct page **)((u8 *)queue + queue_size);
-		queue->kernel_if->page = &queue->kernel_if->header_page[1];
+		queue->kernel_if->u.h.page =
+			&queue->kernel_if->u.h.header_page[1];
 	}
 
 	return queue;
@@ -711,11 +737,12 @@ static int qp_host_get_user_memory(u64 produce_uva,
 				current->mm,
 				(uintptr_t) produce_uva,
 				produce_q->kernel_if->num_pages,
-				1, 0, produce_q->kernel_if->header_page, NULL);
+				1, 0,
+				produce_q->kernel_if->u.h.header_page, NULL);
 	if (retval < produce_q->kernel_if->num_pages) {
 		pr_warn("get_user_pages(produce) failed (retval=%d)", retval);
-		qp_release_pages(produce_q->kernel_if->header_page, retval,
-				 false);
+		qp_release_pages(produce_q->kernel_if->u.h.header_page,
+				 retval, false);
 		err = VMCI_ERROR_NO_MEM;
 		goto out;
 	}
@@ -724,12 +751,13 @@ static int qp_host_get_user_memory(u64 produce_uva,
 				current->mm,
 				(uintptr_t) consume_uva,
 				consume_q->kernel_if->num_pages,
-				1, 0, consume_q->kernel_if->header_page, NULL);
+				1, 0,
+				consume_q->kernel_if->u.h.header_page, NULL);
 	if (retval < consume_q->kernel_if->num_pages) {
 		pr_warn("get_user_pages(consume) failed (retval=%d)", retval);
-		qp_release_pages(consume_q->kernel_if->header_page, retval,
-				 false);
-		qp_release_pages(produce_q->kernel_if->header_page,
+		qp_release_pages(consume_q->kernel_if->u.h.header_page,
+				 retval, false);
+		qp_release_pages(produce_q->kernel_if->u.h.header_page,
 				 produce_q->kernel_if->num_pages, false);
 		err = VMCI_ERROR_NO_MEM;
 	}
@@ -772,15 +800,15 @@ static int qp_host_register_user_memory(struct vmci_qp_page_store *page_store,
 static void qp_host_unregister_user_memory(struct vmci_queue *produce_q,
 					   struct vmci_queue *consume_q)
 {
-	qp_release_pages(produce_q->kernel_if->header_page,
+	qp_release_pages(produce_q->kernel_if->u.h.header_page,
 			 produce_q->kernel_if->num_pages, true);
-	memset(produce_q->kernel_if->header_page, 0,
-	       sizeof(*produce_q->kernel_if->header_page) *
+	memset(produce_q->kernel_if->u.h.header_page, 0,
+	       sizeof(*produce_q->kernel_if->u.h.header_page) *
 	       produce_q->kernel_if->num_pages);
-	qp_release_pages(consume_q->kernel_if->header_page,
+	qp_release_pages(consume_q->kernel_if->u.h.header_page,
 			 consume_q->kernel_if->num_pages, true);
-	memset(consume_q->kernel_if->header_page, 0,
-	       sizeof(*consume_q->kernel_if->header_page) *
+	memset(consume_q->kernel_if->u.h.header_page, 0,
+	       sizeof(*consume_q->kernel_if->u.h.header_page) *
 	       consume_q->kernel_if->num_pages);
 }
 
@@ -803,12 +831,12 @@ static int qp_host_map_queues(struct vmci_queue *produce_q,
 		if (produce_q->q_header != consume_q->q_header)
 			return VMCI_ERROR_QUEUEPAIR_MISMATCH;
 
-		if (produce_q->kernel_if->header_page == NULL ||
-		    *produce_q->kernel_if->header_page == NULL)
+		if (produce_q->kernel_if->u.h.header_page == NULL ||
+		    *produce_q->kernel_if->u.h.header_page == NULL)
 			return VMCI_ERROR_UNAVAILABLE;
 
-		headers[0] = *produce_q->kernel_if->header_page;
-		headers[1] = *consume_q->kernel_if->header_page;
+		headers[0] = *produce_q->kernel_if->u.h.header_page;
+		headers[1] = *consume_q->kernel_if->u.h.header_page;
 
 		produce_q->q_header = vmap(headers, 2, VM_MAP, PAGE_KERNEL);
 		if (produce_q->q_header != NULL) {