[Xen-devel] [Patch v2 2/2] hvmloader: Allow the toolstack to choose WAET optimisations

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Keir Fraser <keir@xxxxxxx>
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Tim Deegan <tim@xxxxxxx>
CC: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
---
 tools/firmware/hvmloader/acpi/acpi2_0.h       |    4 ++++
 tools/firmware/hvmloader/acpi/build.c         |   19 +++++++++++++++++++
 tools/firmware/hvmloader/acpi/static_tables.c |   12 +-----------
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/tools/firmware/hvmloader/acpi/acpi2_0.h 
b/tools/firmware/hvmloader/acpi/acpi2_0.h
index 7b22d80..bebe4e6 100644
--- a/tools/firmware/hvmloader/acpi/acpi2_0.h
+++ b/tools/firmware/hvmloader/acpi/acpi2_0.h
@@ -303,6 +303,10 @@ struct acpi_20_waet {
     struct acpi_header header;
     uint32_t           flags;
 };
+#define ACPI_WAET_RTC_NO_ACK        (1<<0) /* RTC requires no int acknowledge 
*/
+#define ACPI_WAET_TIMER_ONE_READ    (1<<1) /* PM timer requires only one read 
*/
+
+#define ACPI_WAET_DEFAULT_FLAGS (ACPI_WAET_TIMER_ONE_READ)
 
 /*
  * Multiple APIC Flags.
diff --git a/tools/firmware/hvmloader/acpi/build.c 
b/tools/firmware/hvmloader/acpi/build.c
index f1dd3f0..a7f5596 100644
--- a/tools/firmware/hvmloader/acpi/build.c
+++ b/tools/firmware/hvmloader/acpi/build.c
@@ -23,6 +23,8 @@
 #include "ssdt_pm.h"
 #include "../config.h"
 #include "../util.h"
+#include "../hypercall.h"
+#include <xen/hvm/params.h>
 #include <xen/hvm/hvm_xs_strings.h>
 
 #define ACPI_MAX_SECONDARY_TABLES 16
@@ -189,6 +191,9 @@ static struct acpi_20_hpet *construct_hpet(void)
 static struct acpi_20_waet *construct_waet(void)
 {
     struct acpi_20_waet *waet;
+    const char *s;
+    struct xen_hvm_param p =
+        { .domid = DOMID_SELF, .index = HVM_PARAM_RTC_MODE };
 
     waet = mem_alloc(sizeof(*waet), 16);
     if (!waet) return NULL;
@@ -196,8 +201,22 @@ static struct acpi_20_waet *construct_waet(void)
     memcpy(waet, &Waet, sizeof(*waet));
 
     waet->header.length = sizeof(*waet);
+
+    s = xenstore_read("platform/waet-rtc-noack", NULL);
+    if ( s )
+    {
+        if ( !strncmp(s, "1", 1) )
+            waet->flags |= ACPI_WAET_RTC_NO_ACK;
+        else
+            waet->flags &= ~ACPI_WAET_RTC_NO_ACK;
+    }
+
     set_checksum(waet, offsetof(struct acpi_header, checksum), sizeof(*waet));
 
+    /* Inform Xen which RTC mode has been chosen */
+    p.value = !!(waet->flags & ACPI_WAET_RTC_NO_ACK);
+    hypercall_hvm_op(HVMOP_set_param, &p);
+
     return waet;
 }
 
diff --git a/tools/firmware/hvmloader/acpi/static_tables.c 
b/tools/firmware/hvmloader/acpi/static_tables.c
index 323ae31..5c699ba 100644
--- a/tools/firmware/hvmloader/acpi/static_tables.c
+++ b/tools/firmware/hvmloader/acpi/static_tables.c
@@ -136,16 +136,6 @@ struct acpi_20_rsdp Rsdp = {
     .length    = sizeof(struct acpi_20_rsdp)
 };
 
-#define ACPI_WAET_RTC_NO_ACK        (1<<0) /* RTC requires no int acknowledge 
*/
-#define ACPI_WAET_TIMER_ONE_READ    (1<<1) /* PM timer requires only one read 
*/
-
-/*
- * The state of the RTC flag getting passed to the guest must be in
- * sync with the mode selection in the hypervisor RTC emulation code.
- */
-#define ACPI_WAET_FLAGS (ACPI_WAET_RTC_NO_ACK | \
-                         ACPI_WAET_TIMER_ONE_READ)
-
 struct acpi_20_waet Waet = {
     .header = {
         .signature    = ACPI_2_0_WAET_SIGNATURE,
@@ -157,7 +147,7 @@ struct acpi_20_waet Waet = {
         .creator_id   = ACPI_CREATOR_ID,
         .creator_revision = ACPI_CREATOR_REVISION
     },
-    .flags = ACPI_WAET_FLAGS
+    .flags = ACPI_WAET_DEFAULT_FLAGS
 };
 
 /*
-- 
1.7.10.4


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