diff mbox series

[RFC,V6,08/14] x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest

Message ID 20230515165917.1306922-9-ltykernel@gmail.com
State New
Headers
Series x86/hyperv/sev: Add AMD sev-snp enlightened guest support on hyperv |

Commit Message

Tianyu Lan May 15, 2023, 4:59 p.m. UTC 
  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>
---
Change since RFC V2:
       * Fix indentation style
---
 arch/x86/include/asm/mshyperv.h | 44 ++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 11 deletions(-)

Comments

Peter Zijlstra May 16, 2023, 10:29 a.m. UTC | #1 
On Mon, May 15, 2023 at 12:59:10PM -0400, Tianyu Lan wrote:
> 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>
> ---
> Change since RFC V2:
>        * Fix indentation style
> ---
>  arch/x86/include/asm/mshyperv.h | 44 ++++++++++++++++++++++++---------
>  1 file changed, 33 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index 97d117ec95c4..939373791249 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -61,16 +61,25 @@ 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");
> +	}

Wouldn't this generate better code with an alternative?
diff mbox series

Patch

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 97d117ec95c4..939373791249 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -61,16 +61,25 @@  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);
@@ -104,7 +113,13 @@  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)
@@ -149,7 +164,14 @@  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,