On 05/19/2017 07:09 AM, Vitaly Kuznetsov wrote:
Hyper-V supports 'fast' hypercalls when all parameters are passed through
registers. Implement an inline version of a simpliest of these calls:
hypercall with one 8-byte input and no output.
Proper hypercall input interface (struct hv_hypercall_input) definition is
added as well.
Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
Acked-by: K. Y. Srinivasan <k...@microsoft.com>
Tested-by: Simon Xiao <six...@microsoft.com>
Tested-by: Srikanth Myakam <v-...@microsoft.com>
---
arch/x86/include/asm/mshyperv.h | 39 ++++++++++++++++++++++++++++++++++++++
arch/x86/include/uapi/asm/hyperv.h | 19 +++++++++++++++++++
2 files changed, 58 insertions(+)
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index e293937..028e29b 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -216,6 +216,45 @@ static inline u64 hv_do_hypercall(u64 control, void
*input, void *output)
#endif /* !x86_64 */
}
+/* Fast hypercall with 8 bytes of input and no output */
+static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
+{
+ union hv_hypercall_input control = {0};
+
+ control.code = code;
+ control.fast = 1;
+#ifdef CONFIG_X86_64
+ {
+ u64 hv_status;
+
+ __asm__ __volatile__("call *%3"
+ : "=a" (hv_status),
+ "+c" (control.as_uint64), "+d" (input1)
+ : "m" (hv_hypercall_pg)
+ : "cc", "r8", "r9", "r10", "r11");
+ return hv_status;
+ }
+#else
+ {
+ u32 hv_status_hi, hv_status_lo;
+ u32 input1_hi = (u32)(input1 >> 32);
+ u32 input1_lo = (u32)input1;
+
+ __asm__ __volatile__ ("call *%6"
+ : "=d"(hv_status_hi),
+ "=a"(hv_status_lo),
+ "+c"(input1_lo)
+ : "d" (control.as_uint32_hi),
+ "a" (control.as_uint32_lo),
+ "b" (input1_hi),
+ "m" (hv_hypercall_pg)
+ : "cc", "edi", "esi");
+
+ return hv_status_lo | ((u64)hv_status_hi << 32);
+ }
+#endif
This is going to need an explicit "sp" annotation to force a stack
frame, I think. Otherwise objtool is likely to get mad in a
frame-pointer-omitted build.
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