From dd856efafe6097a5c9104725c2bca74430423db8 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Mon, 27 Aug 2012 23:46:17 +0300 Subject: KVM: x86 emulator: access GPRs on demand Instead of populating the entire register file, read in registers as they are accessed, and write back only the modified ones. This saves a VMREAD and VMWRITE on Intel (for rsp, since it is not usually used during emulation), and a two 128-byte copies for the registers. Signed-off-by: Avi Kivity Signed-off-by: Marcelo Tosatti --- arch/x86/include/asm/kvm_emulate.h | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) (limited to 'arch/x86/include/asm/kvm_emulate.h') diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index c764f43b71c5..282aee5d6ac1 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -85,6 +85,19 @@ struct x86_instruction_info { #define X86EMUL_INTERCEPTED 6 /* Intercepted by nested VMCB/VMCS */ struct x86_emulate_ops { + /* + * read_gpr: read a general purpose register (rax - r15) + * + * @reg: gpr number. + */ + ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg); + /* + * write_gpr: write a general purpose register (rax - r15) + * + * @reg: gpr number. + * @val: value to write. + */ + void (*write_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val); /* * read_std: Read bytes of standard (non-emulated/special) memory. * Used for descriptor reading. @@ -281,8 +294,10 @@ struct x86_emulate_ctxt { bool rip_relative; unsigned long _eip; struct operand memop; + u32 regs_valid; /* bitmaps of registers in _regs[] that can be read */ + u32 regs_dirty; /* bitmaps of registers in _regs[] that have been written */ /* Fields above regs are cleared together. */ - unsigned long regs[NR_VCPU_REGS]; + unsigned long _regs[NR_VCPU_REGS]; struct operand *memopp; struct fetch_cache fetch; struct read_cache io_read; @@ -394,4 +409,7 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt, u16 tss_selector, int idt_index, int reason, bool has_error_code, u32 error_code); int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq); +void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt); +void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt); + #endif /* _ASM_X86_KVM_X86_EMULATE_H */ -- cgit v1.2.3