[PATCH] x86/kernel/hyper-v: xmm fast hypercall as guest

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hyper-v hypercall supports fast hypercall and xmm fast hypercall
where argument is exchanged though regular/xmm registers.
This patch implements them and make use of them.
With this patch, pci-hyperv.c, hv_apic.c(__send_ipi_mask), and
hyperv/mmu.c will use (xmm) fast hypercall.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
 arch/x86/hyperv/hv_apic.c           |   3 +-
 arch/x86/hyperv/mmu.c               |   4 +-
 arch/x86/include/asm/hyperv-tlfs.h  |   1 +
 arch/x86/include/asm/mshyperv.h     | 184 ++++++++++++++++++++++++++++++++++--
 drivers/hv/hv.c                     |   3 +-
 drivers/pci/controller/pci-hyperv.c |   5 +-
 6 files changed, 186 insertions(+), 14 deletions(-)

diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index 402338365651..c0cb8180b560 100644
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -173,7 +173,8 @@ static bool __send_ipi_mask(const struct cpumask *mask, int vector)
 		__set_bit(vcpu, (unsigned long *)&ipi_arg->cpu_mask);
 	}
 
-	ret = hv_do_hypercall(HVCALL_SEND_IPI, ipi_arg, NULL);
+	ret = hv_do_hypercall(HVCALL_SEND_IPI, ipi_arg, sizeof(*ipi_arg),
+			      NULL, 0);
 
 ipi_mask_done:
 	local_irq_restore(flags);
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index de27615c51ea..21bf609d01db 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -112,11 +112,11 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
 	if (info->end == TLB_FLUSH_ALL) {
 		flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
 		status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
-					 flush, NULL);
+					 flush, sizeof(*flush), NULL, 0);
 	} else if (info->end &&
 		   ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
 		status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
-					 flush, NULL);
+					 flush, sizeof(*flush), NULL, 0);
 	} else {
 		gva_n = fill_gva_list(flush->gva_list, 0,
 				      info->start, info->end);
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index b8c89265baf0..267112b24a0c 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -123,6 +123,7 @@
  * registers is available
  */
 #define HV_X64_HYPERCALL_PARAMS_XMM_AVAILABLE		(1 << 4)
+#define HV_X64_HYPERCALL_OUTPUT_XMM_AVAILABLE		(1 << 15)
 /* Support for a virtual guest idle state is available */
 #define HV_X64_GUEST_IDLE_STATE_AVAILABLE		(1 << 5)
 /* Guest crash data handler available */
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 5a7375ed5f7c..12f7d5dbd993 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -8,6 +8,7 @@
 #include <asm/io.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/nospec-branch.h>
+#include <asm/fpu/api.h>
 
 #define VP_INVAL	U32_MAX
 
@@ -125,16 +126,13 @@ extern struct clocksource *hyperv_cs;
 extern void *hv_hypercall_pg;
 extern void  __percpu  **hyperv_pcpu_input_arg;
 
-static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
+static inline u64 __hv_do_hypercall(u64 control, void *input, void *output)
 {
 	u64 input_address = input ? virt_to_phys(input) : 0;
 	u64 output_address = output ? virt_to_phys(output) : 0;
 	u64 hv_status;
 
 #ifdef CONFIG_X86_64
-	if (!hv_hypercall_pg)
-		return U64_MAX;
-
 	__asm__ __volatile__("mov %4, %%r8\n"
 			     CALL_NOSPEC
 			     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
@@ -148,9 +146,6 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
 	u32 output_address_hi = upper_32_bits(output_address);
 	u32 output_address_lo = lower_32_bits(output_address);
 
-	if (!hv_hypercall_pg)
-		return U64_MAX;
-
 	__asm__ __volatile__(CALL_NOSPEC
 			     : "=A" (hv_status),
 			       "+c" (input_address_lo), ASM_CALL_CONSTRAINT
@@ -194,6 +189,43 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
 		return hv_status;
 }
 
+/* Fast hypercall with 16 bytes of input and no output */
+static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
+{
+	u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
+
+#ifdef CONFIG_X86_64
+	{
+		__asm__ __volatile__("mov %4, %%r8\n"
+				     CALL_NOSPEC
+				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				       "+c" (control), "+d" (input1)
+				     : "r" (input2),
+				       THUNK_TARGET(hv_hypercall_pg)
+				     : "cc", "r8", "r9", "r10", "r11");
+	}
+#else
+	{
+		u32 input1_hi = upper_32_bits(input1);
+		u32 input1_lo = lower_32_bits(input1);
+		u32 input2_hi = upper_32_bits(input2);
+		u32 input2_lo = lower_32_bits(input2);
+
+		__asm__ __volatile__ (CALL_NOSPEC
+				      : "=A"(hv_status),
+					"+c"(input1_lo),
+					ASM_CALL_CONSTRAINT
+				      : "A" (control),
+					"b" (input1_hi),
+					"D" (input2_hi),
+					"S" (input2_lo),
+					THUNK_TARGET(hv_hypercall_pg)
+				      : "cc", "edi", "esi");
+	}
+#endif
+	return hv_status;
+}
+
 /*
  * Rep hypercalls. Callers of this functions are supposed to ensure that
  * rep_count and varhead_size comply with Hyper-V hypercall definition.
@@ -209,7 +241,7 @@ static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
 	control |= (u64)rep_count << HV_HYPERCALL_REP_COMP_OFFSET;
 
 	do {
-		status = hv_do_hypercall(control, input, output);
+		status = __hv_do_hypercall(control, input, output);
 		if ((status & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS)
 			return status;
 
@@ -226,6 +258,142 @@ static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
 	return status;
 }
 
+#define HV_XMM_BYTE_MAX	112
+
+/* ibytes = fixed header size + var header size + data size in bytes */
+static inline u64 hv_do_xmm_fast_hypercall(
+	u64 control, void *input, size_t ibytes, void *output, size_t obytes)
+{
+	u64 status;
+	u64 input0;
+	u64 input1;
+	u64 tmp[12] __aligned((16));
+
+	BUG_ON(ibytes <= 16);
+	BUG_ON(roundup(ibytes, 16) + obytes > HV_XMM_BYTE_MAX);
+
+	control |= HV_HYPERCALL_FAST_BIT;
+
+	/* it's assumed that there are at least two inputs */
+	input0 = ((u64 *)input)[0];
+	input1 = ((u64 *)input)[1];
+	/*
+	 * If input is aligned and long enough, we can avoid copy
+	 * and directly store it into xmm registers.
+	 * It's a case when hyperv_pcpu_input_arg is used.
+	 */
+	memcpy(tmp, (u8 *)input + 16, ibytes - 16);
+	memset((u8 *)tmp + (ibytes - 16), 0, sizeof(tmp) - (ibytes - 16));
+
+	kernel_fpu_begin();
+	if (ibytes > 2 * 8)
+		__asm__ __volatile__("movdqa %0, %%xmm0" : : "m" (tmp[0]));
+	if (ibytes > 4 * 8)
+		__asm__ __volatile__("movdqa %0, %%xmm1" : : "m" (tmp[2]));
+	if (ibytes > 6 * 8)
+		__asm__ __volatile__("movdqa %0, %%xmm2" : : "m" (tmp[4]));
+	if (ibytes > 8 * 8)
+		__asm__ __volatile__("movdqa %0, %%xmm3" : : "m" (tmp[6]));
+	if (ibytes > 10 * 8)
+		__asm__ __volatile__("movdqa %0, %%xmm4" : : "m" (tmp[8]));
+	if (ibytes > 12 * 8)
+		__asm__ __volatile__("movdqa %0, %%xmm5" : : "m" (tmp[10]));
+
+#ifdef CONFIG_X86_64
+	__asm__ __volatile__("mov %4, %%r8\n"
+			     CALL_NOSPEC
+			     : "=a" (status), ASM_CALL_CONSTRAINT,
+			       "+c" (control), "+d" (input0)
+			     : "r" (input1),
+			       THUNK_TARGET(hv_hypercall_pg)
+			     : "cc", "r8", "r9", "r10", "r11");
+#else
+	{
+		u32 input0_hi = upper_32_bits(input0);
+		u32 input0_lo = lower_32_bits(input0);
+		u32 input1_hi = upper_32_bits(input1);
+		u32 input1_lo = lower_32_bits(input1);
+
+		__asm__ __volatile__ (CALL_NOSPEC
+				      : "=A"(status),
+					"+c"(input0_lo),
+					ASM_CALL_CONSTRAINT
+				      :	"A" (control),
+					"b" (input0_hi),
+					"D"(input1_hi),
+					"S"(input1_lo),
+					THUNK_TARGET(hv_hypercall_pg)
+				      : "cc", "edi", "esi");
+	}
+#endif
+	if (output) {
+		size_t i_end = roundup(ibytes, 16);
+		size_t o_end = i_end + obytes;
+
+		if (i_end <= 2 * 8 && 2 * 8 < o_end)
+			__asm__ __volatile__(
+				"movdqa %%xmm0, %s" : : "m" (tmp[0]));
+		if (i_end <= 4 * 8 && 4 * 8 < o_end)
+			__asm__ __volatile__(
+				"movdqa %%xmm1, %s" : : "m" (tmp[2]));
+		if (i_end <= 6 * 8 && 6 * 8 < o_end)
+			__asm__ __volatile__(
+				"movdqa %%xmm2, %s" : : "m" (tmp[4]));
+		if (i_end <= 8 * 8 && 8 * 8 < o_end)
+			__asm__ __volatile__(
+				"movdqa %%xmm3, %s" : : "m" (tmp[6]));
+		if (i_end <= 10 * 8 && 10 * 8 < o_end)
+			__asm__ __volatile__(
+				"movdqa %%xmm4, %s" : : "m" (tmp[8]));
+		if (i_end <= 12 * 8 && 12 * 8 < o_end)
+			__asm__ __volatile__(
+				"movdqa %%xmm5, %s" : : "m" (tmp[10]));
+		memcpy(output, (u8 *)tmp + i_end - 16, obytes);
+	}
+	kernel_fpu_end();
+	return status;
+}
+
+static inline u64 hv_do_hypercall(
+	u64 control, void *input, size_t ibytes, void *output, size_t obytes)
+{
+	if (unlikely(!hv_hypercall_pg))
+		return U64_MAX;
+
+	/* fast hypercall */
+	if (output == NULL && ibytes <= 16) {
+		u64 tmp[2];
+
+		if (ibytes <= 8) {
+			tmp[0] = 0;
+			memcpy(&tmp, input, ibytes);
+			return hv_do_fast_hypercall8((u16)control, tmp[0]);
+		}
+
+		tmp[1] = 0;
+		memcpy(tmp, input, ibytes);
+		return hv_do_fast_hypercall16((u16)control, tmp[0], tmp[1]);
+	}
+
+	/* xmm fast hypercall */
+	if (static_cpu_has(X86_FEATURE_XMM) &&
+	    ms_hyperv.features & HV_X64_HYPERCALL_PARAMS_XMM_AVAILABLE &&
+	    roundup(ibytes, 16) + obytes <= HV_XMM_BYTE_MAX) {
+		if (output) {
+			if (ms_hyperv.features &
+			    HV_X64_HYPERCALL_OUTPUT_XMM_AVAILABLE)
+				return hv_do_xmm_fast_hypercall(
+					control, input, ibytes, output, obytes);
+		} else {
+			WARN_ON(obytes > 0);
+			return hv_do_xmm_fast_hypercall(
+				control, input, ibytes, output, obytes);
+		}
+	}
+
+	return __hv_do_hypercall(control, input, output);
+}
+
 /*
  * Hypervisor's notion of virtual processor ID is different from
  * Linux' notion of CPU ID. This information can only be retrieved
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 658dc765753b..0c7b7a88fdcd 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -92,7 +92,8 @@ int hv_post_message(union hv_connection_id connection_id,
 	aligned_msg->payload_size = payload_size;
 	memcpy((void *)aligned_msg->payload, payload, payload_size);
 
-	status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL);
+	status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg,
+				 sizeof(*aligned_msg), NULL, 0);
 
 	/* Preemption must remain disabled until after the hypercall
 	 * so some other thread can't get scheduled onto this cpu and
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index f6325f1a89e8..7c229009daba 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -979,8 +979,9 @@ static void hv_irq_unmask(struct irq_data *data)
 		}
 	}
 
-	res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT | (var_size << 17),
-			      params, NULL);
+	res = hv_do_hypercall(
+		HVCALL_RETARGET_INTERRUPT | (var_size << 17),
+		params, sizeof(params) + var_size * 8, NULL, 0);
 
 exit_unlock:
 	spin_unlock_irqrestore(&hbus->retarget_msi_interrupt_lock, flags);
-- 
2.14.1




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