[RFC PATCH 07/17] x86/hyperv: Use vmmcall to implement hvcall in sev-snp enlightened guest

[Tianyu Lan <ltykernel@gmail.com>]

From: Tianyu Lan <tiala@microsoft.com>

In sev-snp enlightened guest, hvcall needs to use vmmcall to trigger
vmexit and notify hypervisor to handle hypercall request.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
 arch/x86/include/asm/mshyperv.h | 66 ++++++++++++++++++++++-----------
 1 file changed, 45 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 9b8c3f638845..28d5429e33c9 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -45,16 +45,25 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
 	u64 hv_status;
 
 #ifdef CONFIG_X86_64
-	if (!hv_hypercall_pg)
-		return U64_MAX;
+	if (hv_isolation_type_en_snp()) {
+		__asm__ __volatile__("mov %4, %%r8\n"
+				"vmmcall"
+				: "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				"+c" (control), "+d" (input_address)
+				:  "r" (output_address)
+				: "cc", "memory", "r8", "r9", "r10", "r11");
+	} else {
+		if (!hv_hypercall_pg)
+			return U64_MAX;
 
-	__asm__ __volatile__("mov %4, %%r8\n"
-			     CALL_NOSPEC
-			     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
-			       "+c" (control), "+d" (input_address)
-			     :  "r" (output_address),
-				THUNK_TARGET(hv_hypercall_pg)
-			     : "cc", "memory", "r8", "r9", "r10", "r11");
+		__asm__ __volatile__("mov %4, %%r8\n"
+				CALL_NOSPEC
+				: "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				"+c" (control), "+d" (input_address)
+				:  "r" (output_address),
+					THUNK_TARGET(hv_hypercall_pg)
+				: "cc", "memory", "r8", "r9", "r10", "r11");
+	}
 #else
 	u32 input_address_hi = upper_32_bits(input_address);
 	u32 input_address_lo = lower_32_bits(input_address);
@@ -82,12 +91,18 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
 	u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
 
 #ifdef CONFIG_X86_64
-	{
+	if (hv_isolation_type_en_snp()) {
+		__asm__ __volatile__(
+				"vmmcall"
+				: "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				"+c" (control), "+d" (input1)
+				:: "cc", "r8", "r9", "r10", "r11");
+	} else {
 		__asm__ __volatile__(CALL_NOSPEC
-				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
-				       "+c" (control), "+d" (input1)
-				     : THUNK_TARGET(hv_hypercall_pg)
-				     : "cc", "r8", "r9", "r10", "r11");
+				: "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				"+c" (control), "+d" (input1)
+				: THUNK_TARGET(hv_hypercall_pg)
+				: "cc", "r8", "r9", "r10", "r11");
 	}
 #else
 	{
@@ -113,14 +128,21 @@ 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
-	{
+	if (hv_isolation_type_en_snp()) {
 		__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");
+				"vmmcall"
+				: "=a" (hv_status), ASM_CALL_CONSTRAINT,
+				"+c" (control), "+d" (input1)
+				: "r" (input2)
+				: "cc", "r8", "r9", "r10", "r11");
+	} else {
+		__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
 	{
@@ -177,6 +199,7 @@ int hv_map_ioapic_interrupt(int ioapic_id, bool level, int vcpu, int vector,
 		struct hv_interrupt_entry *entry);
 int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry);
 int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible);
+int hv_snp_boot_ap(int cpu, unsigned long start_ip);
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 void hv_ghcb_msr_write(u64 msr, u64 value);
@@ -191,6 +214,7 @@ static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {}
 #endif
 
 extern bool hv_isolation_type_snp(void);
+extern bool hv_isolation_type_en_snp(void);
 
 static inline bool hv_is_synic_reg(unsigned int reg)
 {
-- 
2.25.1