Rusty Russell
2007-Apr-18 13:02 UTC
[PATCH] Update lguest's patch code for new paravirt patch architecture
The new patching code means that we don't actually have to do as much work in lguest's patcher. We use paravirt_patch_default() for cases we don't want to patch inline, which automatically handles the "patch iret to use a direct jump" case. There's no measurable effect on lguest's virtbench scores tho. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> --- drivers/lguest/lguest.c | 10 ++-------- drivers/lguest/lguest_asm.S | 1 - 2 files changed, 2 insertions(+), 9 deletions(-) ==================================================================--- a/drivers/lguest/lguest.c +++ b/drivers/lguest/lguest.c @@ -388,7 +388,6 @@ static const struct lguest_insns [PARAVIRT_PATCH(irq_enable)] = { lgstart_sti, lgend_sti }, [PARAVIRT_PATCH(restore_fl)] = { lgstart_popf, lgend_popf }, [PARAVIRT_PATCH(save_fl)] = { lgstart_pushf, lgend_pushf }, - [PARAVIRT_PATCH(iret)] = { lgstart_iret, lgend_iret }, }; static unsigned lguest_patch(u8 type, u16 clobber, void *insns, unsigned len) { @@ -396,20 +395,15 @@ static unsigned lguest_patch(u8 type, u1 /* Don't touch it if we don't have a replacement */ if (type >= ARRAY_SIZE(lguest_insns) || !lguest_insns[type].start) - return len; + return paravirt_patch_default(type, clobber, insns, len); insn_len = lguest_insns[type].end - lguest_insns[type].start; /* Similarly if we can't fit replacement. */ if (len < insn_len) - return len; + return paravirt_patch_default(type, clobber, insns, len); memcpy(insns, lguest_insns[type].start, insn_len); - if (type == PARAVIRT_PATCH(iret)) { - /* Jumps are relative. */ - u32 off = (u32)lguest_iret - ((u32)insns + insn_len); - memcpy(insns+1, &off, sizeof(off)); - } return insn_len; } ==================================================================--- a/drivers/lguest/lguest_asm.S +++ b/drivers/lguest/lguest_asm.S @@ -34,7 +34,6 @@ LGUEST_PATCH(sti, movl $X86_EFLAGS_IF, l LGUEST_PATCH(sti, movl $X86_EFLAGS_IF, lguest_data+LGUEST_DATA_irq_enabled) LGUEST_PATCH(popf, movl %eax, lguest_data+LGUEST_DATA_irq_enabled) LGUEST_PATCH(pushf, movl lguest_data+LGUEST_DATA_irq_enabled, %eax) -LGUEST_PATCH(iret, .byte 0xE9,0,0,0,0) /* jmp <to-be-patched> */ .text /* These demark the EIP range where host should never deliver interrupts. */
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