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Subject[PATCH V4 5/9] x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest
Date
From: Tianyu Lan <tiala@microsoft.com>

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>
---
arch/x86/include/asm/mshyperv.h | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 2fa38e9f6207..025eda129d99 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -64,12 +64,12 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
if (!hv_hypercall_pg)
return U64_MAX;

- __asm__ __volatile__("mov %4, %%r8\n"
- CALL_NOSPEC
+ __asm__ __volatile__("mov %[output], %%r8\n"
+ ALTERNATIVE("vmmcall", CALL_NOSPEC, X86_FEATURE_SEV_ES)
: "=a" (hv_status), ASM_CALL_CONSTRAINT,
- "+c" (control), "+d" (input_address)
- : "r" (output_address),
- THUNK_TARGET(hv_hypercall_pg)
+ "+c" (control), "+d" (input_address)
+ : [output] "r" (output_address),
+ THUNK_TARGET(hv_hypercall_pg)
: "cc", "memory", "r8", "r9", "r10", "r11");
#else
u32 input_address_hi = upper_32_bits(input_address);
@@ -105,7 +105,8 @@ static inline u64 _hv_do_fast_hypercall8(u64 control, u64 input1)

#ifdef CONFIG_X86_64
{
- __asm__ __volatile__(CALL_NOSPEC
+ __asm__ __volatile__("mov %[thunk_target], %%r8\n"
+ ALTERNATIVE("vmmcall", CALL_NOSPEC, X86_FEATURE_SEV_ES)
: "=a" (hv_status), ASM_CALL_CONSTRAINT,
"+c" (control), "+d" (input1)
: THUNK_TARGET(hv_hypercall_pg)
@@ -150,13 +151,13 @@ static inline u64 _hv_do_fast_hypercall16(u64 control, u64 input1, u64 input2)

#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");
+ __asm__ __volatile__("mov %[output], %%r8\n"
+ ALTERNATIVE("vmmcall", CALL_NOSPEC, X86_FEATURE_SEV_ES)
+ : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+ "+c" (control), "+d" (input1)
+ : [output] "r" (input2),
+ THUNK_TARGET(hv_hypercall_pg)
+ : "cc", "r8", "r9", "r10", "r11");
}
#else
{
--
2.25.1
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