[Xen-changelog] [xen master] ARM: introduce vgic_access_guest_memory()

[patchbot@xxxxxxx]

commit 1ba52a57247c33a09a88a52742611d5ffc8c6ed9
Author:     Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxxxxxxxxxx>
AuthorDate: Thu Apr 6 12:28:22 2017 +0100
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Wed Jun 14 11:38:37 2017 -0700

    ARM: introduce vgic_access_guest_memory()
    
    This function allows to copy a chunk of data from and to guest physical
    memory. It looks up the associated page from the guest's p2m tree
    and maps this page temporarily for the time of the access.
    This function was originally written by Vijaya as part of an earlier series:
    https://patchwork.kernel.org/patch/8177251
    
    Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxxxxxxxxxx>
    Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
    Reviewed-by: Julien Grall <julien.grall@xxxxxxx>
    Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/arch/arm/vgic.c        | 50 ++++++++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/vgic.h |  3 +++
 2 files changed, 53 insertions(+)

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index c097bd4..789c58b 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -20,6 +20,7 @@
 #include <xen/bitops.h>
 #include <xen/lib.h>
 #include <xen/init.h>
+#include <xen/domain_page.h>
 #include <xen/softirq.h>
 #include <xen/irq.h>
 #include <xen/sched.h>
@@ -636,6 +637,55 @@ void vgic_free_virq(struct domain *d, unsigned int virq)
 }
 
 /*
+ * Temporarily map one physical guest page and copy data to or from it.
+ * The data to be copied cannot cross a page boundary.
+ */
+int vgic_access_guest_memory(struct domain *d, paddr_t gpa, void *buf,
+                             uint32_t size, bool is_write)
+{
+    struct page_info *page;
+    uint64_t offset = gpa & ~PAGE_MASK;  /* Offset within the mapped page */
+    p2m_type_t p2mt;
+    void *p;
+
+    /* Do not cross a page boundary. */
+    if ( size > (PAGE_SIZE - offset) )
+    {
+        printk(XENLOG_G_ERR "d%d: vITS: memory access would cross page 
boundary\n",
+               d->domain_id);
+        return -EINVAL;
+    }
+
+    page = get_page_from_gfn(d, paddr_to_pfn(gpa), &p2mt, P2M_ALLOC);
+    if ( !page )
+    {
+        printk(XENLOG_G_ERR "d%d: vITS: Failed to get table entry\n",
+               d->domain_id);
+        return -EINVAL;
+    }
+
+    if ( !p2m_is_ram(p2mt) )
+    {
+        put_page(page);
+        printk(XENLOG_G_ERR "d%d: vITS: memory used by the ITS should be RAM.",
+               d->domain_id);
+        return -EINVAL;
+    }
+
+    p = __map_domain_page(page);
+
+    if ( is_write )
+        memcpy(p + offset, buf, size);
+    else
+        memcpy(buf, p + offset, size);
+
+    unmap_domain_page(p);
+    put_page(page);
+
+    return 0;
+}
+
+/*
  * Local variables:
  * mode: C
  * c-file-style: "BSD"
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index 33b2fb5..6a23249 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -320,6 +320,9 @@ extern void register_vgic_ops(struct domain *d, const 
struct vgic_ops *ops);
 int vgic_v2_init(struct domain *d, int *mmio_count);
 int vgic_v3_init(struct domain *d, int *mmio_count);
 
+int vgic_access_guest_memory(struct domain *d, paddr_t gpa, void *buf,
+                             uint32_t size, bool_t is_write);
+
 extern int domain_vgic_register(struct domain *d, int *mmio_count);
 extern int vcpu_vgic_free(struct vcpu *v);
 extern bool vgic_to_sgi(struct vcpu *v, register_t sgir,
--
generated by git-patchbot for /home/xen/git/xen.git#master

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