When the 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 guest operating system.
Add the hypercall so that the ACRN guest can communicate with the low-level ACRN hypervisor. On x86 it is implemented with the VMCALL instruction. Co-developed-by: Jason Chen CJ <jason.cj.c...@intel.com> Signed-off-by: Jason Chen CJ <jason.cj.c...@intel.com> Signed-off-by: Zhao Yakui <yakui.z...@intel.com> Reviewed-by: Thomas Gleixner <t...@linutronix.de> --- 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. Use the "VMCALL" mnemonic in comment/commit log. Uppercase r8/rdi/rsi/rax for hypercall parameter register in comment. v5->v6: Remove explicit local register variable for inline assembly --- arch/x86/include/asm/acrn_hypercall.h | 84 +++++++++++++++++++++++++++++++++++ 1 file changed, 84 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..5cb438e --- /dev/null +++ b/arch/x86/include/asm/acrn_hypercall.h @@ -0,0 +1,84 @@ +/* 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) +{ + long result; + + /* the hypercall is implemented with the VMCALL instruction. + * volatile qualifier is added to avoid that it is dropped + * because of compiler optimization. + */ + asm volatile("movq %[hcall_id], %%r8\n\t" + "vmcall\n\t" + : "=a" (result) + : [hcall_id] "g" (hcall_id) + : "r8"); + + return result; +} + +static inline long acrn_hypercall1(unsigned long hcall_id, + unsigned long param1) +{ + long result; + + asm volatile("movq %[hcall_id], %%r8\n\t" + "vmcall\n\t" + : "=a" (result) + : [hcall_id] "g" (hcall_id), "D" (param1) + : "r8"); + + return result; +} + +static inline long acrn_hypercall2(unsigned long hcall_id, + unsigned long param1, + unsigned long param2) +{ + long result; + + asm volatile("movq %[hcall_id], %%r8\n\t" + "vmcall\n\t" + : "=a" (result) + : [hcall_id] "g" (hcall_id), "D" (param1), "S" (param2) + : "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