Commit 8a0a8719 authored by Shuo Liu's avatar Shuo Liu Committed by Greg Kroah-Hartman
Browse files

x86/acrn: Introduce hypercall interfaces 



The Service VM communicates with the hypervisor via conventional
hypercalls. VMCALL instruction is used to make the hypercalls.

ACRN hypercall ABI:
  * Hypercall number is in R8 register.
  * Up to 2 parameters are in RDI and RSI registers.
  * Return value is in RAX register.

Introduce the ACRN hypercall interfaces. Because GCC doesn't support R8
register as direct register constraints, use supported constraint as
input with a explicit MOV to R8 in beginning of asm.

Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Fengwei Yin <fengwei.yin@intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Yu Wang <yu1.wang@intel.com>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Originally-by: default avatarYakui Zhao <yakui.zhao@intel.com>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Acked-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarShuo Liu <shuo.a.liu@intel.com>
Link: https://lore.kernel.org/r/20210207031040.49576-5-shuo.a.liu@intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ebbfc978

arch/x86/include/asm/acrn.h

+54 −0
Original line number Diff line number Diff line
@@ -21,4 +21,58 @@ static inline u32 acrn_cpuid_base(void) 
	return 0;

}



/*

 * Hypercalls for ACRN

 *

 * - VMCALL instruction is used to implement ACRN hypercalls.

 * - ACRN hypercall ABI:

 *   - Hypercall number is passed in R8 register.

 *   - Up to 2 arguments are passed in RDI, RSI.

 *   - Return value will be placed in RAX.

 *

 * Because GCC doesn't support R8 register as direct register constraints, use

 * supported constraint as input with a explicit MOV to R8 in beginning of asm.

 */

static inline long acrn_hypercall0(unsigned long hcall_id)

{

	long result;



	asm volatile("movl %1, %%r8d\n\t"

		     "vmcall\n\t"

		     : "=a" (result)

		     : "g" (hcall_id)

		     : "r8", "memory");



	return result;

}



static inline long acrn_hypercall1(unsigned long hcall_id,

				   unsigned long param1)

{

	long result;



	asm volatile("movl %1, %%r8d\n\t"

		     "vmcall\n\t"

		     : "=a" (result)

		     : "g" (hcall_id), "D" (param1)

		     : "r8", "memory");



	return result;

}



static inline long acrn_hypercall2(unsigned long hcall_id,

				   unsigned long param1,

				   unsigned long param2)

{

	long result;



	asm volatile("movl %1, %%r8d\n\t"

		     "vmcall\n\t"

		     : "=a" (result)

		     : "g" (hcall_id), "D" (param1), "S" (param2)

		     : "r8", "memory");



	return result;

}



#endif /* _ASM_X86_ACRN_H */