x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest

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

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20230818102919.1318039-6-ltykernel@gmail.com

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 9f11f04..8660d6b 100644 (file)
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -48,6 +48,8 @@ extern u64 hv_current_partition_id;
 
 extern union hv_ghcb * __percpu *hv_ghcb_pg;
 
+extern bool hv_isolation_type_en_snp(void);
+
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
 int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
@@ -59,6 +61,16 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
        u64 hv_status;
 
 #ifdef CONFIG_X86_64
+       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");
+               return hv_status;
+       }
+
        if (!hv_hypercall_pg)
                return U64_MAX;
 
@@ -102,7 +114,13 @@ static inline u64 _hv_do_fast_hypercall8(u64 control, u64 input1)
        u64 hv_status;
 
 #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)
@@ -147,7 +165,14 @@ static inline u64 _hv_do_fast_hypercall16(u64 control, u64 input1, u64 input2)
        u64 hv_status;
 
 #ifdef CONFIG_X86_64
-       {
+       if (hv_isolation_type_en_snp()) {
+               __asm__ __volatile__("mov %4, %%r8\n"
+                                    "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,
@@ -240,7 +265,6 @@ static inline void hv_vtom_init(void) {}
 #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)
 {