From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34145) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cIxsO-00076e-RY for qemu-devel@nongnu.org; Mon, 19 Dec 2016 08:21:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cIxsN-0007aS-Us for qemu-devel@nongnu.org; Mon, 19 Dec 2016 08:21:12 -0500 Received: from mail.ispras.ru ([83.149.199.45]:46250) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cIxsN-0007aD-Ng for qemu-devel@nongnu.org; Mon, 19 Dec 2016 08:21:11 -0500 From: Pavel Dovgalyuk Date: Mon, 19 Dec 2016 16:21:11 +0300 Message-ID: <20161219132111.3016.50241.stgit@PASHA-ISP> In-Reply-To: <20161219132102.3016.46687.stgit@PASHA-ISP> References: <20161219132102.3016.46687.stgit@PASHA-ISP> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] [PATCH v6 1/9] icount: update instruction counter on apic patching List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, quintela@redhat.com, jasowang@redhat.com, mst@redhat.com, pbonzini@redhat.com kvmvapic patches the code when some instructions are executed. E.g. mov 0xff, 0xfffe0080 is interpreted as push 0xff/call ... This patching is also followed by some side effects (changing apic and guest memory state). Therefore deterministic execution should take this operation into account. This patch decreases icount when original mov instruction is trying to execute. Therefore patching becomes deterministic and can be replayed correctly. Signed-off-by: Pavel Dovgalyuk --- hw/i386/kvmvapic.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c index b30d1b9..146d47c 100644 --- a/hw/i386/kvmvapic.c +++ b/hw/i386/kvmvapic.c @@ -412,6 +412,12 @@ static void patch_instruction(VAPICROMState *s, X86CPU *cpu, target_ulong ip) if (!kvm_enabled()) { cpu_get_tb_cpu_state(env, ¤t_pc, ¤t_cs_base, ¤t_flags); + /* Account this instruction, because we will exit the tb. + This is the first instruction in the block. Therefore + there is no need in restoring CPU state. */ + if (use_icount) { + --cs->icount_decr.u16.low; + } } pause_all_vcpus();