[Xen-devel] [PATCH v2 2/3] hvmloader: Introduce cpuid_count() helper function

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Also promote the regular cpuid() function to a static inline in util.h, as
this offers far better register in the generated code than an unconditional
call into a separate translation unit.

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/util.c |    9 ---------
 tools/firmware/hvmloader/util.h |   17 ++++++++++++++---
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/tools/firmware/hvmloader/util.c b/tools/firmware/hvmloader/util.c
index 80d822f..29da0d5 100644
--- a/tools/firmware/hvmloader/util.c
+++ b/tools/firmware/hvmloader/util.c
@@ -306,15 +306,6 @@ memcmp(const void *s1, const void *s2, unsigned n)
     return 0;
 }
 
-void
-cpuid(uint32_t idx, uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
-{
-    asm volatile (
-        "cpuid"
-        : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx)
-        : "0" (idx) );
-}
-
 static const char hex_digits[] = "0123456789abcdef";
 
 /* Write a two-character hex representation of 'byte' to digits[].
diff --git a/tools/firmware/hvmloader/util.h b/tools/firmware/hvmloader/util.h
index a70e4aa..b3853e3 100644
--- a/tools/firmware/hvmloader/util.h
+++ b/tools/firmware/hvmloader/util.h
@@ -97,9 +97,20 @@ int uart_exists(uint16_t uart_base);
 int lpt_exists(uint16_t lpt_base);
 int hpet_exists(unsigned long hpet_base);
 
-/* Do cpuid instruction, with operation 'idx' */
-void cpuid(uint32_t idx, uint32_t *eax, uint32_t *ebx,
-           uint32_t *ecx, uint32_t *edx);
+static inline void cpuid(uint32_t idx, uint32_t *eax,
+                         uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
+{
+    asm volatile ("cpuid" : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx)
+                  : "0" (idx));
+}
+
+static inline void cpuid_count(uint32_t idx, uint32_t subleaf, uint32_t *eax,
+                               uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
+{
+    asm volatile ("cpuid" : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx)
+                  : "0" (idx), "2" (subleaf));
+}
+
 
 /* Read the TSC register. */
 static inline uint64_t rdtsc(void)
-- 
1.7.10.4


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