[Xen-devel] [RFC XEN PATCH v3 31/39] tools/libacpi: add callback to translate GPA to GVA

[Haozhong Zhang <haozhong.zhang@xxxxxxxxx>]

The location of ACPI blobs passed from device modeil is offered in
guest physical address. libacpi needs to convert the guest physical
address to guest virtual address before it can access those ACPI
blobs.

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 c2218d9fcb..2f8a4654b0 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)
 {
@@ -989,6 +994,7 @@ 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 2ef854eb8f..e9fe6c6e79 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(v) ((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 157f63f7bc..f5a1c384bc 100644
--- a/tools/libacpi/libacpi.h
+++ b/tools/libacpi/libacpi.h
@@ -51,6 +51,7 @@ 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 3b79b2179b..b14136949c 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;
-- 
2.14.1


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