From: Chang S. Bae Date: Fri, 15 May 2026 17:27:32 +0000 (-0400) Subject: KVM: VMX: Macrofy GPR swapping in __vmx_vcpu_run() X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c3029c38175b66b8ed8713f6c6c028a1de998b0d;p=thirdparty%2Flinux.git KVM: VMX: Macrofy GPR swapping in __vmx_vcpu_run() Convert the repeated register save/restore sequences into macros, trading some level of implementation trickiness for conciseness (more than one register can be saved/restored with one invocation) and a smaller chance of cut and paste errors. This is particularly useful in preparation for extended GPR support; upcoming support for APX would need to add 32 lines to the VM entry/exit paths. No functional change intended. Suggested-by: Paolo Bonzini Signed-off-by: Chang S. Bae Link: https://lore.kernel.org/6e67df0e-e5f0-43f5-aa86-22e8b01b75d2@redhat.com Link: https://patch.msgid.link/20260512011502.53072-2-chang.seok.bae@intel.com/ [Keep kvm_vcpu_regs.h and put the macros in there. -Paolo] Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/include/asm/kvm_vcpu_regs.h b/arch/x86/include/asm/kvm_vcpu_regs.h index 1af2cb59233b5..650fabf5871dc 100644 --- a/arch/x86/include/asm/kvm_vcpu_regs.h +++ b/arch/x86/include/asm/kvm_vcpu_regs.h @@ -22,4 +22,108 @@ #define __VCPU_REGS_R15 15 #endif +#ifdef __ASSEMBLER__ + +#define REG_NUM_INVALID 100 + + # convert the 32-bit register operand \r32 into a register number; + # store it in the value whose name is in \opd. + # only for !CONFIG_X86_64 (does not support r8d-r15d) + .macro R32_NUM opd r32 + \opd = REG_NUM_INVALID + .ifc \r32,%eax + \opd = __VCPU_REGS_RAX + .endif + .ifc \r32,%ecx + \opd = __VCPU_REGS_RCX + .endif + .ifc \r32,%edx + \opd = __VCPU_REGS_RDX + .endif + .ifc \r32,%ebx + \opd = __VCPU_REGS_RBX + .endif + .ifc \r32,%esp + \opd = __VCPU_REGS_RSP + .endif + .ifc \r32,%ebp + \opd = __VCPU_REGS_RBP + .endif + .ifc \r32,%esi + \opd = __VCPU_REGS_RSI + .endif + .ifc \r32,%edi + \opd = __VCPU_REGS_RDI + .endif + .endm + + # convert the 64-bit register operand \r64 into a register number; + # store it in the value whose name is in \opd. + .macro R64_NUM opd r64 + \opd = REG_NUM_INVALID +#ifdef CONFIG_X86_64 + .ifc \r64,%rax + \opd = __VCPU_REGS_RAX + .endif + .ifc \r64,%rcx + \opd = __VCPU_REGS_RCX + .endif + .ifc \r64,%rdx + \opd = __VCPU_REGS_RDX + .endif + .ifc \r64,%rbx + \opd = __VCPU_REGS_RBX + .endif + .ifc \r64,%rsp + \opd = __VCPU_REGS_RSP + .endif + .ifc \r64,%rbp + \opd = __VCPU_REGS_RBP + .endif + .ifc \r64,%rsi + \opd = __VCPU_REGS_RSI + .endif + .ifc \r64,%rdi + \opd = __VCPU_REGS_RDI + .endif + .ifc \r64,%r8 + \opd = 8 + .endif + .ifc \r64,%r9 + \opd = 9 + .endif + .ifc \r64,%r10 + \opd = 10 + .endif + .ifc \r64,%r11 + \opd = 11 + .endif + .ifc \r64,%r12 + \opd = 12 + .endif + .ifc \r64,%r13 + \opd = 13 + .endif + .ifc \r64,%r14 + \opd = 14 + .endif + .ifc \r64,%r15 + \opd = 15 + .endif +#endif + .endm + +.macro REG_NUM reg_num reg +#ifdef CONFIG_X86_64 + R64_NUM \reg_num \reg +#else + R32_NUM \reg_num \reg +#endif + .if \reg_num == REG_NUM_INVALID + .error "invalid register" + .endif +.endm + +#endif + #endif /* _ASM_X86_KVM_VCPU_REGS_H */ diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S index f523d9e498398..6a91e1383e8f8 100644 --- a/arch/x86/kvm/svm/vmenter.S +++ b/arch/x86/kvm/svm/vmenter.S @@ -4,13 +4,10 @@ #include #include #include -#include #include #include "kvm-asm-offsets.h" #include "vmenter.h" -#define WORD_SIZE (BITS_PER_LONG / 8) - /* Intentionally omit RAX as it's context switched by hardware */ #define VCPU_RCX (SVM_vcpu_arch_regs + __VCPU_REGS_RCX * WORD_SIZE) #define VCPU_RDX (SVM_vcpu_arch_regs + __VCPU_REGS_RDX * WORD_SIZE) diff --git a/arch/x86/kvm/vmenter.h b/arch/x86/kvm/vmenter.h index ba3f71449c62c..77376812c81ba 100644 --- a/arch/x86/kvm/vmenter.h +++ b/arch/x86/kvm/vmenter.h @@ -2,6 +2,8 @@ #ifndef __KVM_X86_VMENTER_H #define __KVM_X86_VMENTER_H +#include + #define KVM_ENTER_VMRESUME BIT(0) #define KVM_ENTER_SAVE_SPEC_CTRL BIT(1) #define KVM_ENTER_CLEAR_CPU_BUFFERS_FOR_MMIO BIT(2) @@ -76,5 +78,34 @@ wrmsr .endm +#define WORD_SIZE (BITS_PER_LONG / 8) + +.macro LOAD_REGS src:req, regs_ofs:req, regs:vararg +.irp reg, \regs + REG_NUM reg_num \reg + mov (\regs_ofs + reg_num * WORD_SIZE)(\src), \reg +.endr +.endm + +.macro STORE_REGS dst:req, regs_ofs:req, regs:vararg +.irp reg, \regs + REG_NUM reg_num \reg + mov \reg, (\regs_ofs + reg_num * WORD_SIZE)(\dst) +.endr +.endm + +.macro POP_REGS dst:req, regs_ofs:req, regs:vararg +.irp reg, \regs + REG_NUM reg_num \reg + pop (\regs_ofs + reg_num * WORD_SIZE)(\dst) +.endr +.endm + +.macro CLEAR_REGS regs:vararg +.irp reg, \regs + xorl \reg, \reg +.endr +.endm + #endif /* __ASSEMBLER__ */ #endif /* __KVM_X86_VMENTER_H */ diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S index 7e4dc17fc0b87..4b7aaa7430fb0 100644 --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -2,35 +2,12 @@ #include #include #include -#include #include #include #include #include "kvm-asm-offsets.h" #include "vmenter.h" -#define WORD_SIZE (BITS_PER_LONG / 8) - -#define VCPU_RAX (VMX_vcpu_arch_regs + __VCPU_REGS_RAX * WORD_SIZE) -#define VCPU_RCX (VMX_vcpu_arch_regs + __VCPU_REGS_RCX * WORD_SIZE) -#define VCPU_RDX (VMX_vcpu_arch_regs + __VCPU_REGS_RDX * WORD_SIZE) -#define VCPU_RBX (VMX_vcpu_arch_regs + __VCPU_REGS_RBX * WORD_SIZE) -/* Intentionally omit RSP as it's context switched by hardware */ -#define VCPU_RBP (VMX_vcpu_arch_regs + __VCPU_REGS_RBP * WORD_SIZE) -#define VCPU_RSI (VMX_vcpu_arch_regs + __VCPU_REGS_RSI * WORD_SIZE) -#define VCPU_RDI (VMX_vcpu_arch_regs + __VCPU_REGS_RDI * WORD_SIZE) - -#ifdef CONFIG_X86_64 -#define VCPU_R8 (VMX_vcpu_arch_regs + __VCPU_REGS_R8 * WORD_SIZE) -#define VCPU_R9 (VMX_vcpu_arch_regs + __VCPU_REGS_R9 * WORD_SIZE) -#define VCPU_R10 (VMX_vcpu_arch_regs + __VCPU_REGS_R10 * WORD_SIZE) -#define VCPU_R11 (VMX_vcpu_arch_regs + __VCPU_REGS_R11 * WORD_SIZE) -#define VCPU_R12 (VMX_vcpu_arch_regs + __VCPU_REGS_R12 * WORD_SIZE) -#define VCPU_R13 (VMX_vcpu_arch_regs + __VCPU_REGS_R13 * WORD_SIZE) -#define VCPU_R14 (VMX_vcpu_arch_regs + __VCPU_REGS_R14 * WORD_SIZE) -#define VCPU_R15 (VMX_vcpu_arch_regs + __VCPU_REGS_R15 * WORD_SIZE) -#endif - .macro VMX_DO_EVENT_IRQOFF call_insn call_target /* * Unconditionally create a stack frame, getting the correct RSP on the @@ -114,25 +91,18 @@ SYM_FUNC_START(__vmx_vcpu_run) * an LFENCE to stop speculation from skipping the wrmsr. */ - /* Load guest registers. Don't clobber flags. */ - mov VCPU_RAX(%_ASM_DI), %_ASM_AX - mov VCPU_RCX(%_ASM_DI), %_ASM_CX - mov VCPU_RDX(%_ASM_DI), %_ASM_DX - mov VCPU_RBX(%_ASM_DI), %_ASM_BX - mov VCPU_RBP(%_ASM_DI), %_ASM_BP - mov VCPU_RSI(%_ASM_DI), %_ASM_SI + /* + * Load guest registers. Don't clobber flags. Intentionally omit + * %_ASM_SP as it's context switched by hardware + */ + LOAD_REGS %_ASM_DI, VMX_vcpu_arch_regs, \ + %_ASM_AX, %_ASM_CX, %_ASM_DX, %_ASM_BX, %_ASM_BP, %_ASM_SI #ifdef CONFIG_X86_64 - mov VCPU_R8 (%_ASM_DI), %r8 - mov VCPU_R9 (%_ASM_DI), %r9 - mov VCPU_R10(%_ASM_DI), %r10 - mov VCPU_R11(%_ASM_DI), %r11 - mov VCPU_R12(%_ASM_DI), %r12 - mov VCPU_R13(%_ASM_DI), %r13 - mov VCPU_R14(%_ASM_DI), %r14 - mov VCPU_R15(%_ASM_DI), %r15 + LOAD_REGS %_ASM_DI, VMX_vcpu_arch_regs, \ + %r8, %r9, %r10, %r11, %r12, %r13, %r14, %r15 #endif /* Load guest RDI. This kills the @vmx pointer! */ - mov VCPU_RDI(%_ASM_DI), %_ASM_DI + LOAD_REGS %_ASM_DI, VMX_vcpu_arch_regs, %_ASM_DI /* * Note, ALTERNATIVE_2 works in reverse order. If CLEAR_CPU_BUF_VM is @@ -187,23 +157,16 @@ SYM_INNER_LABEL_ALIGN(vmx_vmexit, SYM_L_GLOBAL) /* Reload @vmx to RDI. */ mov 2*WORD_SIZE(%_ASM_SP), %_ASM_DI - /* Save all guest registers, including RDI from the stack */ - mov %_ASM_AX, VCPU_RAX(%_ASM_DI) - mov %_ASM_CX, VCPU_RCX(%_ASM_DI) - mov %_ASM_DX, VCPU_RDX(%_ASM_DI) - mov %_ASM_BX, VCPU_RBX(%_ASM_DI) - mov %_ASM_BP, VCPU_RBP(%_ASM_DI) - mov %_ASM_SI, VCPU_RSI(%_ASM_DI) - pop VCPU_RDI(%_ASM_DI) + /* + * Save all guest registers, including RDI from the stack. Intentionally + * omit %_ASM_SP as it's context switched by hardware + */ + STORE_REGS %_ASM_DI, VMX_vcpu_arch_regs, \ + %_ASM_AX, %_ASM_CX, %_ASM_DX, %_ASM_BX, %_ASM_BP, %_ASM_SI + POP_REGS %_ASM_DI, VMX_vcpu_arch_regs, %_ASM_DI #ifdef CONFIG_X86_64 - mov %r8, VCPU_R8 (%_ASM_DI) - mov %r9, VCPU_R9 (%_ASM_DI) - mov %r10, VCPU_R10(%_ASM_DI) - mov %r11, VCPU_R11(%_ASM_DI) - mov %r12, VCPU_R12(%_ASM_DI) - mov %r13, VCPU_R13(%_ASM_DI) - mov %r14, VCPU_R14(%_ASM_DI) - mov %r15, VCPU_R15(%_ASM_DI) + STORE_REGS %_ASM_DI, VMX_vcpu_arch_regs, \ + %r8, %r9, %r10, %r11, %r12, %r13, %r14, %r15 #endif /* Clear return value to indicate VM-Exit (as opposed to VM-Fail). */ @@ -220,21 +183,9 @@ SYM_INNER_LABEL_ALIGN(vmx_vmexit, SYM_L_GLOBAL) * VM-Exit and RBX is explicitly loaded with 0 or 1 to hold the return * value. */ - xor %eax, %eax - xor %ecx, %ecx - xor %edx, %edx - xor %ebp, %ebp - xor %esi, %esi - xor %edi, %edi + CLEAR_REGS %eax, %ecx, %edx, %ebp, %esi, %edi #ifdef CONFIG_X86_64 - xor %r8d, %r8d - xor %r9d, %r9d - xor %r10d, %r10d - xor %r11d, %r11d - xor %r12d, %r12d - xor %r13d, %r13d - xor %r14d, %r14d - xor %r15d, %r15d + CLEAR_REGS %r8d, %r9d, %r10d, %r11d, %r12d, %r13d, %r14d, %r15d #endif /*