[Xen-devel] [RFC XEN PATCH v2 08/15] tools/libacpi: add callback acpi_ctxt.p2v to get a pointer from physical address

[Haozhong Zhang <haozhong.zhang@xxxxxxxxx>]

The address of ACPI blobs passed from device model is provided via
XenStore as the physical address. libacpi needs this callback to
access them.

Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/firmware/hvmloader/util.c |  6 ++++++
 tools/firmware/hvmloader/util.h |  1 +
 tools/libacpi/libacpi.h         |  1 +
 tools/libxl/libxl_x86_acpi.c    | 10 ++++++++++
 4 files changed, 18 insertions(+)

diff --git a/tools/firmware/hvmloader/util.c b/tools/firmware/hvmloader/util.c
index d289361317..b2372a75be 100644
--- a/tools/firmware/hvmloader/util.c
+++ b/tools/firmware/hvmloader/util.c
@@ -871,6 +871,11 @@ static unsigned long acpi_v2p(struct acpi_ctxt *ctxt, void 
*v)
     return virt_to_phys(v);
 }
 
+static void *acpi_p2v(struct acpi_ctxt *ctxt, unsigned long p)
+{
+    return phys_to_virt(p);
+}
+
 static void *acpi_mem_alloc(struct acpi_ctxt *ctxt,
                             uint32_t size, uint32_t align)
 {
@@ -970,6 +975,7 @@ void hvmloader_acpi_build_tables(struct acpi_config *config,
     ctxt.mem_ops.alloc = acpi_mem_alloc;
     ctxt.mem_ops.free = acpi_mem_free;
     ctxt.mem_ops.v2p = acpi_v2p;
+    ctxt.mem_ops.p2v = acpi_p2v;
 
     ctxt.min_alloc_byte_align = 16;
 
diff --git a/tools/firmware/hvmloader/util.h b/tools/firmware/hvmloader/util.h
index 6062f0b8cf..6a50dae1eb 100644
--- a/tools/firmware/hvmloader/util.h
+++ b/tools/firmware/hvmloader/util.h
@@ -200,6 +200,7 @@ xen_pfn_t mem_hole_alloc(uint32_t nr_mfns);
 /* Allocate memory in a reserved region below 4GB. */
 void *mem_alloc(uint32_t size, uint32_t align);
 #define virt_to_phys(v) ((unsigned long)(v))
+#define phys_to_virt(p) ((void *)(p))
 
 /* Allocate memory in a scratch region */
 void *scratch_alloc(uint32_t size, uint32_t align);
diff --git a/tools/libacpi/libacpi.h b/tools/libacpi/libacpi.h
index 2049a1b032..48acf9583c 100644
--- a/tools/libacpi/libacpi.h
+++ b/tools/libacpi/libacpi.h
@@ -50,6 +50,7 @@ struct acpi_ctxt {
         void *(*alloc)(struct acpi_ctxt *ctxt, uint32_t size, uint32_t align);
         void (*free)(struct acpi_ctxt *ctxt, void *v, uint32_t size);
         unsigned long (*v2p)(struct acpi_ctxt *ctxt, void *v);
+        void *(*p2v)(struct acpi_ctxt *ctxt, unsigned long p);
     } mem_ops;
 
     uint32_t min_alloc_byte_align; /* minimum alignment used by mem_ops.alloc 
*/
diff --git a/tools/libxl/libxl_x86_acpi.c b/tools/libxl/libxl_x86_acpi.c
index f242450166..2622e03ce6 100644
--- a/tools/libxl/libxl_x86_acpi.c
+++ b/tools/libxl/libxl_x86_acpi.c
@@ -52,6 +52,15 @@ static unsigned long virt_to_phys(struct acpi_ctxt *ctxt, 
void *v)
             libxl_ctxt->alloc_base_paddr);
 }
 
+static void *phys_to_virt(struct acpi_ctxt *ctxt, unsigned long p)
+{
+    struct libxl_acpi_ctxt *libxl_ctxt =
+        CONTAINER_OF(ctxt, struct libxl_acpi_ctxt, c);
+
+    return (void *)((p - libxl_ctxt->alloc_base_paddr) +
+                    libxl_ctxt->alloc_base_vaddr);
+}
+
 static void *mem_alloc(struct acpi_ctxt *ctxt,
                        uint32_t size, uint32_t align)
 {
@@ -181,6 +190,7 @@ int libxl__dom_load_acpi(libxl__gc *gc,
 
     libxl_ctxt.c.mem_ops.alloc = mem_alloc;
     libxl_ctxt.c.mem_ops.v2p = virt_to_phys;
+    libxl_ctxt.c.mem_ops.p2v = phys_to_virt;
     libxl_ctxt.c.mem_ops.free = acpi_mem_free;
 
     libxl_ctxt.c.min_alloc_byte_align = 16;
-- 
2.12.0


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