xen/grant: Implement an grant frame array struct (v3).

The 'xen_hvm_resume_frames' used to be an 'unsigned long'
and contain the virtual address of the grants. That was OK
for most architectures (PVHVM, ARM) were the grants are contiguous
in memory. That however is not the case for PVH - in which case
we will have to do a lookup for each virtual address for the PFN.

Instead of doing that, lets make it a structure which will contain
the array of PFNs, the virtual address and the count of said PFNs.

Also provide a generic functions: gnttab_setup_auto_xlat_frames and
gnttab_free_auto_xlat_frames to populate said structure with
appropriate values for PVHVM and ARM.

To round it off, change the name from 'xen_hvm_resume_frames' to
a more descriptive one - 'xen_auto_xlat_grant_frames'.

For PVH, in patch "xen/pvh: Piggyback on PVHVM for grant driver"
we will populate the 'xen_auto_xlat_grant_frames' by ourselves.

v2 moves the xen_remap in the gnttab_setup_auto_xlat_frames
and also introduces xen_unmap for gnttab_free_auto_xlat_frames.

Suggested-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v3: Based on top of 'asm/xen/page.h: remove redundant semicolon']
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
index ac6789aad05985a0c68acfbd7e22373d0833781f..709c4b4d2f1dbaa60a5a5b701ab65b04606b4868 100644 (file)
--- a/arch/arm/include/asm/xen/page.h
+++ b/arch/arm/include/asm/xen/page.h
@@ -118,5 +118,6 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 }
 
 #define xen_remap(cookie, size) ioremap_cached((cookie), (size))
+#define xen_unmap(cookie) iounmap((cookie))
 
 #endif /* _ASM_ARM_XEN_PAGE_H */

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 85501238b4258316272f9448ad8829b18a1111b2..2162172c0ddc765e62011c8d2a8b4006786550cf 100644 (file)
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -208,6 +208,7 @@ static int __init xen_guest_init(void)
        const char *version = NULL;
        const char *xen_prefix = "xen,xen-";
        struct resource res;
+       unsigned long grant_frames;
 
        node = of_find_compatible_node(NULL, NULL, "xen,xen");
        if (!node) {
@@ -224,10 +225,10 @@ static int __init xen_guest_init(void)
        }
        if (of_address_to_resource(node, GRANT_TABLE_PHYSADDR, &res))
                return 0;
-       xen_hvm_resume_frames = res.start;
+       grant_frames = res.start;
        xen_events_irq = irq_of_parse_and_map(node, 0);
        pr_info("Xen %s support found, events_irq=%d gnttab_frame_pfn=%lx\n",
-                       version, xen_events_irq, (xen_hvm_resume_frames >> PAGE_SHIFT));
+                       version, xen_events_irq, (grant_frames >> PAGE_SHIFT));
        xen_domain_type = XEN_HVM_DOMAIN;
 
        xen_setup_features();
@@ -265,6 +266,10 @@ static int __init xen_guest_init(void)
        if (xen_vcpu_info == NULL)
                return -ENOMEM;
 
+       if (gnttab_setup_auto_xlat_frames(grant_frames)) {
+               free_percpu(xen_vcpu_info);
+               return -ENOMEM;
+       }
        gnttab_init();
        if (!xen_initial_domain())
                xenbus_probe(NULL);

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 4a092ccdd1471d6ea5246e5801936468808244f8..3e276eb23d1bd7c315f055ecfcb551b0cd5ed1b8 100644 (file)
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -227,5 +227,6 @@ void make_lowmem_page_readonly(void *vaddr);
 void make_lowmem_page_readwrite(void *vaddr);
 
 #define xen_remap(cookie, size) ioremap((cookie), (size));
+#define xen_unmap(cookie) iounmap((cookie))
 
 #endif /* _ASM_X86_XEN_PAGE_H */

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index e69c7780c208a60feeaecf419f7ede1c00135306..44b75ccfbbff86d312e8d9e84862154881bd236d 100644 (file)
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -65,8 +65,7 @@ static unsigned int nr_grant_frames;
 static int gnttab_free_count;
 static grant_ref_t gnttab_free_head;
 static DEFINE_SPINLOCK(gnttab_list_lock);
-unsigned long xen_hvm_resume_frames;
-EXPORT_SYMBOL_GPL(xen_hvm_resume_frames);
+struct grant_frames xen_auto_xlat_grant_frames;
 
 static union {
        struct grant_entry_v1 *v1;
@@ -838,6 +837,51 @@ unsigned int gnttab_max_grant_frames(void)
 }
 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
 
+int gnttab_setup_auto_xlat_frames(unsigned long addr)
+{
+       xen_pfn_t *pfn;
+       unsigned int max_nr_gframes = __max_nr_grant_frames();
+       unsigned int i;
+       void *vaddr;
+
+       if (xen_auto_xlat_grant_frames.count)
+               return -EINVAL;
+
+       vaddr = xen_remap(addr, PAGE_SIZE * max_nr_gframes);
+       if (vaddr == NULL) {
+               pr_warn("Failed to ioremap gnttab share frames (addr=0x%08lx)!\n",
+                       addr);
+               return -ENOMEM;
+       }
+       pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
+       if (!pfn) {
+               xen_unmap(vaddr);
+               return -ENOMEM;
+       }
+       for (i = 0; i < max_nr_gframes; i++)
+               pfn[i] = PFN_DOWN(addr) + i;
+
+       xen_auto_xlat_grant_frames.vaddr = vaddr;
+       xen_auto_xlat_grant_frames.pfn = pfn;
+       xen_auto_xlat_grant_frames.count = max_nr_gframes;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
+
+void gnttab_free_auto_xlat_frames(void)
+{
+       if (!xen_auto_xlat_grant_frames.count)
+               return;
+       kfree(xen_auto_xlat_grant_frames.pfn);
+       xen_unmap(xen_auto_xlat_grant_frames.vaddr);
+
+       xen_auto_xlat_grant_frames.pfn = NULL;
+       xen_auto_xlat_grant_frames.count = 0;
+       xen_auto_xlat_grant_frames.vaddr = NULL;
+}
+EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
+
 /* Handling of paged out grant targets (GNTST_eagain) */
 #define MAX_DELAY 256
 static inline void
@@ -1068,6 +1112,7 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
                struct xen_add_to_physmap xatp;
                unsigned int i = end_idx;
                rc = 0;
+               BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
                /*
                 * Loop backwards, so that the first hypercall has the largest
                 * index, ensuring that the table will grow only once.
@@ -1076,7 +1121,7 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
                        xatp.domid = DOMID_SELF;
                        xatp.idx = i;
                        xatp.space = XENMAPSPACE_grant_table;
-                       xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i;
+                       xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
                        rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
                        if (rc != 0) {
                                pr_warn("grant table add_to_physmap failed, err=%d\n",
@@ -1174,11 +1219,10 @@ static int gnttab_setup(void)
                return -ENOSYS;
 
        if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL) {
-               gnttab_shared.addr = xen_remap(xen_hvm_resume_frames,
-                                               PAGE_SIZE * max_nr_gframes);
+               gnttab_shared.addr = xen_auto_xlat_grant_frames.vaddr;
                if (gnttab_shared.addr == NULL) {
-                       pr_warn("Failed to ioremap gnttab share frames (addr=0x%08lx)!\n",
-                                       xen_hvm_resume_frames);
+                       pr_warn("gnttab share frames (addr=0x%08lx) is not mapped!\n",
+                               (unsigned long)xen_auto_xlat_grant_frames.vaddr);
                        return -ENOMEM;
                }
        }

diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
index 2f3528e93cb9be0f576ede425b31637d3a92c018..f1947ac218d99fa533d3f2257886ed91f6b3211e 100644 (file)
--- a/drivers/xen/platform-pci.c
+++ b/drivers/xen/platform-pci.c
@@ -108,6 +108,7 @@ static int platform_pci_init(struct pci_dev *pdev,
        long ioaddr;
        long mmio_addr, mmio_len;
        unsigned int max_nr_gframes;
+       unsigned long grant_frames;
 
        if (!xen_domain())
                return -ENODEV;
@@ -154,13 +155,16 @@ static int platform_pci_init(struct pci_dev *pdev,
        }
 
        max_nr_gframes = gnttab_max_grant_frames();
-       xen_hvm_resume_frames = alloc_xen_mmio(PAGE_SIZE * max_nr_gframes);
+       grant_frames = alloc_xen_mmio(PAGE_SIZE * max_nr_gframes);
+       if (gnttab_setup_auto_xlat_frames(grant_frames))
+               goto out;
        ret = gnttab_init();
        if (ret)
-               goto out;
+               goto grant_out;
        xenbus_probe(NULL);
        return 0;
-
+grant_out:
+       gnttab_free_auto_xlat_frames();
 out:
        pci_release_region(pdev, 0);
 mem_out:

diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 694dcaf266e635335dfdaf22994624d3d5e3d9d4..5acb1e4ac0d339cb0e71b62653f4bd5e70cdc638 100644 (file)
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -178,8 +178,15 @@ int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
                           grant_status_t **__shared);
 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
 
-extern unsigned long xen_hvm_resume_frames;
+struct grant_frames {
+       xen_pfn_t *pfn;
+       unsigned int count;
+       void *vaddr;
+};
+extern struct grant_frames xen_auto_xlat_grant_frames;
 unsigned int gnttab_max_grant_frames(void);
+int gnttab_setup_auto_xlat_frames(unsigned long addr);
+void gnttab_free_auto_xlat_frames(void);
 
 #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))