From f23b070e662ca55a8fdaaa28537af06cab664499 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Thu, 26 Jul 2012 13:12:22 +0800 Subject: [PATCH] KVM: x86 emulator: simplify read_emulated No need split mmio read region into 8-bits pieces since we do it in emulator_read_write_onepage Changelog: Add a WARN_ON to check read-cache overflow Acked-by: Marcelo Tosatti Signed-off-by: Xiao Guangrong Signed-off-by: Avi Kivity --- arch/x86/kvm/emulate.c | 31 ++++++++++++++----------------- 1 file changed, 14 insertions(+), 17 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 85b611e13e84..2c5d1e65d9d1 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1166,24 +1166,21 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt, int rc; struct read_cache *mc = &ctxt->mem_read; - while (size) { - int n = min(size, 8u); - size -= n; - if (mc->pos < mc->end) - goto read_cached; - - rc = ctxt->ops->read_emulated(ctxt, addr, mc->data + mc->end, n, - &ctxt->exception); - if (rc != X86EMUL_CONTINUE) - return rc; - mc->end += n; + if (mc->pos < mc->end) + goto read_cached; - read_cached: - memcpy(dest, mc->data + mc->pos, n); - mc->pos += n; - dest += n; - addr += n; - } + WARN_ON((mc->end + size) >= sizeof(mc->data)); + + rc = ctxt->ops->read_emulated(ctxt, addr, mc->data + mc->end, size, + &ctxt->exception); + if (rc != X86EMUL_CONTINUE) + return rc; + + mc->end += size; + +read_cached: + memcpy(dest, mc->data + mc->pos, size); + mc->pos += size; return X86EMUL_CONTINUE; } -- 2.20.1