[Xen-devel] [RFC XEN PATCH 11/23] riscv: Add guestcopy.c

[Bobby Eshleman <bobbyeshleman@gmail.com>]

From: Alistair Francis <alistair.francis@wdc.com>

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 xen/arch/riscv/guestcopy.c | 158 +++++++++++++++++++++++++++++++++++++
 1 file changed, 158 insertions(+)
 create mode 100644 xen/arch/riscv/guestcopy.c

diff --git a/xen/arch/riscv/guestcopy.c b/xen/arch/riscv/guestcopy.c
new file mode 100644
index 0000000000..c2f7700eab
--- /dev/null
+++ b/xen/arch/riscv/guestcopy.c
@@ -0,0 +1,158 @@
+#include <xen/lib.h>
+#include <xen/domain_page.h>
+#include <xen/mm.h>
+#include <xen/sched.h>
+#include <asm/current.h>
+#include <asm/guest_access.h>
+
+#define COPY_flush_dcache   (1U << 0)
+#define COPY_from_guest     (0U << 1)
+#define COPY_to_guest       (1U << 1)
+#define COPY_ipa            (0U << 2)
+#define COPY_linear         (1U << 2)
+
+typedef union
+{
+    struct
+    {
+        struct vcpu *v;
+    } gva;
+
+    struct
+    {
+        struct domain *d;
+    } gpa;
+} copy_info_t;
+
+#define GVA_INFO(vcpu) ((copy_info_t) { .gva = { vcpu } })
+#define GPA_INFO(domain) ((copy_info_t) { .gpa = { domain } })
+
+static struct page_info *translate_get_page(copy_info_t info, uint64_t addr,
+                                            bool linear, bool write)
+{
+    p2m_type_t p2mt;
+    struct page_info *page;
+
+    page = get_page_from_gfn(info.gpa.d, paddr_to_pfn(addr), &p2mt, P2M_ALLOC);
+
+    if ( !page )
+        return NULL;
+
+    if ( !p2m_is_ram(p2mt) )
+    {
+        put_page(page);
+        return NULL;
+    }
+
+    return page;
+}
+
+static unsigned long copy_guest(void *buf, uint64_t addr, unsigned int len,
+                                copy_info_t info, unsigned int flags)
+{
+    /* XXX needs to handle faults */
+    unsigned offset = addr & ~PAGE_MASK;
+
+    BUILD_BUG_ON((sizeof(addr)) < sizeof(vaddr_t));
+    BUILD_BUG_ON((sizeof(addr)) < sizeof(paddr_t));
+
+    while ( len )
+    {
+        void *p;
+        unsigned size = min(len, (unsigned)PAGE_SIZE - offset);
+        struct page_info *page;
+
+        page = translate_get_page(info, addr, flags & COPY_linear,
+                                  flags & COPY_to_guest);
+        if ( page == NULL )
+            return len;
+
+        p = __map_domain_page(page);
+        p += offset;
+        if ( flags & COPY_to_guest )
+        {
+            /*
+             * buf will be NULL when the caller request to zero the
+             * guest memory.
+             */
+            if ( buf )
+                memcpy(p, buf, size);
+            else
+                memset(p, 0, size);
+        }
+        else
+            memcpy(buf, p, size);
+
+        if ( flags & COPY_flush_dcache )
+            clean_dcache_va_range(p, size);
+
+        unmap_domain_page(p - offset);
+        put_page(page);
+        len -= size;
+        buf += size;
+        addr += size;
+        /*
+         * After the first iteration, guest virtual address is correctly
+         * aligned to PAGE_SIZE.
+         */
+        offset = 0;
+    }
+
+    return 0;
+}
+
+unsigned long raw_copy_to_guest(void *to, const void *from, unsigned len)
+{
+    return copy_guest((void *)from, (vaddr_t)to, len,
+                      GVA_INFO(current), COPY_to_guest | COPY_linear);
+}
+
+unsigned long raw_copy_to_guest_flush_dcache(void *to, const void *from,
+                                             unsigned len)
+{
+    return copy_guest((void *)from, (vaddr_t)to, len, GVA_INFO(current),
+                      COPY_to_guest | COPY_flush_dcache | COPY_linear);
+}
+
+unsigned long raw_clear_guest(void *to, unsigned len)
+{
+    return copy_guest(NULL, (vaddr_t)to, len, GVA_INFO(current),
+                      COPY_to_guest | COPY_linear);
+}
+
+unsigned long raw_copy_from_guest(void *to, const void __user *from, unsigned len)
+{
+    return copy_guest(to, (vaddr_t)from, len, GVA_INFO(current),
+                      COPY_from_guest | COPY_linear);
+}
+
+unsigned long copy_to_guest_phys_flush_dcache(struct domain *d,
+                                              paddr_t gpa,
+                                              void *buf,
+                                              unsigned int len)
+{
+    return copy_guest(buf, gpa, len, GPA_INFO(d),
+                      COPY_to_guest | COPY_ipa | COPY_flush_dcache);
+}
+
+int access_guest_memory_by_ipa(struct domain *d, paddr_t gpa, void *buf,
+                               uint32_t size, bool is_write)
+{
+    unsigned long left;
+    int flags = COPY_ipa;
+
+    flags |= is_write ? COPY_to_guest : COPY_from_guest;
+
+    left = copy_guest(buf, gpa, size, GPA_INFO(d), flags);
+
+    return (!left) ? 0 : -EINVAL;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
2.25.0


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