Messages in this thread Patch in this message | | | From | Zhao Yakui <> | Subject | [RFC PATCH v5 4/4] x86/acrn: Add hypercall for ACRN guest | Date | Wed, 24 Apr 2019 08:54:20 +0800 |
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When ACRN hypervisor is detected, the hypercall is needed so that the ACRN guest can query/config some settings. For example: it can be used to query the resources in hypervisor and manage the CPU/memory/device/ interrupt for the guest operating system.
So add the hypercall so that ACRN guest can communicate with the low-level ACRN hypervisor. It is implemented with the VMCALL instruction.
Co-developed-by: Jason Chen CJ <jason.cj.chen@intel.com> Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com> Signed-off-by: Zhao Yakui <yakui.zhao@intel.com> --- V1->V2: Refine the comments for the function of acrn_hypercall0/1/2 v2->v3: Use the "vmcall" mnemonic to replace hard-code byte definition v4->v5: Use _ASM_X86_ACRN_HYPERCALL_H instead of _ASM_X86_ACRNHYPERCALL_H to align the header file of acrn_hypercall.h Use the "VMCALL" mnemonic in comment/commit log. Uppercase r8/rdi/rsi/rax for hypercall parameter registers in comment. --- arch/x86/include/asm/acrn_hypercall.h | 82 +++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 arch/x86/include/asm/acrn_hypercall.h
diff --git a/arch/x86/include/asm/acrn_hypercall.h b/arch/x86/include/asm/acrn_hypercall.h new file mode 100644 index 0000000..3594436 --- /dev/null +++ b/arch/x86/include/asm/acrn_hypercall.h @@ -0,0 +1,82 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_X86_ACRN_HYPERCALL_H +#define _ASM_X86_ACRN_HYPERCALL_H + +#include <linux/errno.h> + +#ifdef CONFIG_ACRN_GUEST + +/* + * Hypercalls for ACRN guest + * + * Hypercall number is passed in R8 register. + * Up to 2 arguments are passed in RDI, RSI. + * Return value will be placed in RAX. + */ + +static inline long acrn_hypercall0(unsigned long hcall_id) +{ + register unsigned long r8 asm("r8") = hcall_id; + register long result asm("rax"); + + /* the hypercall is implemented with the VMCALL instruction. + * asm indicates that inline assembler instruction is used. + * volatile qualifier is added to avoid that it is dropped + * because of compiler optimization. + */ + asm volatile("vmcall" + : "=r"(result) + : "r"(r8)); + + return result; +} + +static inline long acrn_hypercall1(unsigned long hcall_id, + unsigned long param1) +{ + register unsigned long r8 asm("r8") = hcall_id; + register long result asm("rax"); + + asm volatile("vmcall" + : "=r"(result) + : "D"(param1), "r"(r8)); + + return result; +} + +static inline long acrn_hypercall2(unsigned long hcall_id, + unsigned long param1, + unsigned long param2) +{ + register unsigned long r8 asm("r8") = hcall_id; + register long result asm("rax"); + + asm volatile("vmcall" + : "=r"(result) + : "D"(param1), "S"(param2), "r"(r8)); + + return result; +} + +#else + +static inline long acrn_hypercall0(unsigned long hcall_id) +{ + return -ENOTSUPP; +} + +static inline long acrn_hypercall1(unsigned long hcall_id, + unsigned long param1) +{ + return -ENOTSUPP; +} + +static inline long acrn_hypercall2(unsigned long hcall_id, + unsigned long param1, + unsigned long param2) +{ + return -ENOTSUPP; +} +#endif /* CONFIG_ACRN_GUEST */ +#endif /* _ASM_X86_ACRN_HYPERCALL_H */ -- 2.7.4
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