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[PATCH v4 04/10] x86/hyper-v: fast hypercall implementation

From Vitaly Kuznetsov <vkuznets@redhat.com>
Newsgroups linux.kernel
Subject [PATCH v4 04/10] x86/hyper-v: fast hypercall implementation
Date 2017-05-24 14:10 +0200
Message-ID <tKDh0-2cD-21@gated-at.bofh.it> (permalink)
References <tKDh0-2cD-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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 <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Simon Xiao <sixiao@microsoft.com>
Tested-by: Srikanth Myakam <v-srm@microsoft.com>
---
Change since v3:
- Force stack frame in hv_do_fast_hypercall8() [Andy Lutomirski]
---
 arch/x86/include/asm/mshyperv.h    | 41 ++++++++++++++++++++++++++++++++++++++
 arch/x86/include/uapi/asm/hyperv.h | 19 ++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index cbbf7db..52b3611 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -217,6 +217,47 @@ 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};
+	register void *__sp asm(_ASM_SP);
+
+	control.code = code;
+	control.fast = 1;
+#ifdef CONFIG_X86_64
+	{
+		u64 hv_status;
+
+		__asm__ __volatile__("call *%4"
+				     : "=a" (hv_status), "+r" (__sp),
+				       "+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 *%7"
+				      : "=d"(hv_status_hi),
+					"=a"(hv_status_lo),
+					"+c"(input1_lo),
+					"+r"(__sp)
+				      :	"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
+}
+
 void hyperv_init(void);
 void hyperv_report_panic(struct pt_regs *regs);
 bool hv_is_hypercall_page_setup(void);
diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
index 432df4b..c87e900 100644
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -256,6 +256,25 @@
 #define HV_PROCESSOR_POWER_STATE_C2		2
 #define HV_PROCESSOR_POWER_STATE_C3		3
 
+/* Hypercall interface */
+union hv_hypercall_input {
+	u64 as_uint64;
+	struct {
+		__u32 as_uint32_lo;
+		__u32 as_uint32_hi;
+	};
+	struct {
+		__u64 code:16;
+		__u64 fast:1;
+		__u64 varhead_size:10;
+		__u64 reserved1:5;
+		__u64 rep_count:12;
+		__u64 reserved2:4;
+		__u64 rep_start:12;
+		__u64 reserved3:4;
+	};
+};
+
 /* hypercall status code */
 #define HV_STATUS_SUCCESS			0
 #define HV_STATUS_INVALID_HYPERCALL_CODE	2
-- 
2.9.4

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Thread

[PATCH v4 00/10] Hyper-V: praravirtualized remote TLB flushing and hypercall improvements Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
  [PATCH v4 06/10] x86/hyper-v: implement rep hypercalls Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
  [PATCH v4 09/10] x86/hyper-v: support extended CPU ranges for TLB flush hypercalls Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
    Re: [PATCH v4 09/10] x86/hyper-v: support extended CPU ranges for TLB  flush hypercalls Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-05-27 20:20 +0200
  [PATCH v4 01/10] x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
  [PATCH v4 03/10] x86/hyper-v: make hv_do_hypercall() inline Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
    Re: [PATCH v4 03/10] x86/hyper-v: make hv_do_hypercall() inline Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-05-27 19:50 +0200
  [PATCH v4 04/10] x86/hyper-v: fast hypercall implementation Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
    Re: [PATCH v4 04/10] x86/hyper-v: fast hypercall implementation Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-05-27 19:50 +0200
  [PATCH v4 08/10] x86/hyper-v: use hypercall for remote TLB flush Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
  [PATCH v4 05/10] hyper-v: use fast hypercall for HVCALL_SIGNAL_EVENT Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
    Re: [PATCH v4 05/10] hyper-v: use fast hypercall for HVCALL_SIGNAL_EVENT Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-05-27 20:00 +0200
  [PATCH v4 02/10] x86/hyper-v: stash the max number of virtual/logical processor Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
    Re: [PATCH v4 02/10] x86/hyper-v: stash the max number of  virtual/logical processor Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-05-27 19:50 +0200
      Re: [PATCH v4 02/10] x86/hyper-v: stash the max number of  virtual/logical processor Steven Rostedt <rostedt@goodmis.org> - 2017-06-05 17:30 +0200
        Re: [PATCH v4 02/10] x86/hyper-v: stash the max number of  virtual/logical processor Stephen Hemminger <stephen@networkplumber.org> - 2017-06-05 17:40 +0200
  [PATCH v4 10/10] tracing/hyper-v: trace hyperv_mmu_flush_tlb_others() Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-24 14:10 +0200
    Re: [PATCH v4 10/10] tracing/hyper-v: trace  hyperv_mmu_flush_tlb_others() Steven Rostedt <rostedt@goodmis.org> - 2017-06-05 18:00 +0200
      Re: [PATCH v4 10/10] tracing/hyper-v: trace hyperv_mmu_flush_tlb_others() Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-06-05 18:20 +0200
        Re: [PATCH v4 10/10] tracing/hyper-v: trace  hyperv_mmu_flush_tlb_others() Steven Rostedt <rostedt@goodmis.org> - 2017-06-07 16:00 +0200
          Re: [PATCH v4 10/10] tracing/hyper-v: trace hyperv_mmu_flush_tlb_others() Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-06-07 16:10 +0200

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