From nobody Tue May 21 00:33:06 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=linux.ibm.com ARC-Seal: i=1; a=rsa-sha256; t=1662393084; cv=none; d=zohomail.com; s=zohoarc; b=MC7T8LDHn/TEcc+ceVWCQcS7wrSpgDapu+bPKTIgkS9xh3Hjz4Y+kbkVKeBSdbEypXFbCjNciCWLaiTHm3Ak4wznKBvX03QD/2eGAGXwuBEmF3s8MKwxyNJLzh/vRGUjrUevs4N3SudoU30BJDnYxYs7EsGtbgXFi6tgYb1cowk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1662393084; h=Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=eLN52ewhCRoeGT/iRfkvTU2sBWQ26qFuAD7fd7sjkGQ=; b=ZJVrCsMNnB6WHv8a2Aw/vpoW0NzF3YtgkbAQ+mI0XG2ie6LDwUXeTCjYy26sQOr1wvHvxuM4WxUSnCtRPNbWVrElpN2IoUjaCsV7J21FThwbWDrNKZvOqKO/pv7Nkj+HLxbRc3rzoXDwe1TT0RUKCn+vdziSs5fHz1WMtqUWw1I= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1662393084466452.2243559611651; Mon, 5 Sep 2022 08:51:24 -0700 (PDT) Received: from localhost ([::1]:33322 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oVENe-0000Tf-O5 for importer@patchew.org; Mon, 05 Sep 2022 11:51:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59870) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oVEMI-0008BO-BO for qemu-devel@nongnu.org; Mon, 05 Sep 2022 11:49:58 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:14658) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oVEMG-0003yb-55 for qemu-devel@nongnu.org; Mon, 05 Sep 2022 11:49:57 -0400 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 285FmF9a020448; Mon, 5 Sep 2022 15:49:52 GMT Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3jdm2xg18x-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 05 Sep 2022 15:49:51 +0000 Received: from m0098410.ppops.net (m0098410.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 285Fnp1v029919; Mon, 5 Sep 2022 15:49:51 GMT Received: from ppma03fra.de.ibm.com (6b.4a.5195.ip4.static.sl-reverse.com [149.81.74.107]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3jdm2xg188-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 05 Sep 2022 15:49:51 +0000 Received: from pps.filterd (ppma03fra.de.ibm.com [127.0.0.1]) by ppma03fra.de.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 285FeDN9021725; Mon, 5 Sep 2022 15:49:48 GMT Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by ppma03fra.de.ibm.com with ESMTP id 3jbxj8sy65-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 05 Sep 2022 15:49:48 +0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 285Fnjk832768428 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 5 Sep 2022 15:49:46 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D249611C050; Mon, 5 Sep 2022 15:49:45 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 83FAA11C04C; Mon, 5 Sep 2022 15:49:45 +0000 (GMT) Received: from heavy.lan (unknown [9.171.53.58]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 5 Sep 2022 15:49:45 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=eLN52ewhCRoeGT/iRfkvTU2sBWQ26qFuAD7fd7sjkGQ=; b=Gzc8ajNCl5tRvfQiYDLReGNxfgvOD7fjujsheA+yRgZ9whtjg27OFKsOvulk2xnUy6eu pnxdr6f7ryUOVpnc/ldhbCeo/RddCanLMMGVITcKf2vNfS+55q98beFI3O8vjlq9Uuxp 5anMibq51ewV1wNWkXbf0FPHwaRLSLXzVZU1IzbwPDkyS1L1SY2D/9BgHJeOOLGJYmB9 IKDCp7/zPVnJdOuHuKWMIPksYjvtiT0XL/4N1S2MCN0ZiTCo0HxTVF+bCiIi830i5xWN Wo28QtH5S8P9DQ1G6nfx+ZcMcQ1yIe0+s/VkTvoUYRQLlrUS3ss7Q7VhjlkoVWeQ8E/d BA== From: Ilya Leoshkevich To: Paolo Bonzini , Richard Henderson , Eduardo Habkost Cc: qemu-devel@nongnu.org, Ilya Leoshkevich Subject: [PATCH v2] tests/tcg/x86_64: add cross-modifying code test Date: Mon, 5 Sep 2022 17:49:44 +0200 Message-Id: <20220905154944.1284289-1-iii@linux.ibm.com> X-Mailer: git-send-email 2.37.2 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: AMJeZIUwsuet9w7bSzHFt6gMOb7KDgz- X-Proofpoint-GUID: acAGTe5neXPUP7aSYSK3iMH8CRto7H7Q Content-Transfer-Encoding: quoted-printable X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-05_12,2022-09-05_03,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 suspectscore=0 lowpriorityscore=0 malwarescore=0 mlxlogscore=999 adultscore=0 priorityscore=1501 mlxscore=0 spamscore=0 phishscore=0 bulkscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000 definitions=main-2209050075 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=148.163.156.1; envelope-from=iii@linux.ibm.com; helo=mx0a-001b2d01.pphosted.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @ibm.com) X-ZM-MESSAGEID: 1662393085354100001 Content-Type: text/plain; charset="utf-8" commit f025692c992c ("accel/tcg: Clear PAGE_WRITE before translation") fixed cross-modifying code handling, but did not add a test. The changed code was further improved recently [1], and I was not sure whether these modifications were safe (spoiler: they were fine). Add a test to make sure there are no regressions. [1] https://lists.gnu.org/archive/html/qemu-devel/2022-09/msg00034.html Signed-off-by: Ilya Leoshkevich --- v1: https://lists.gnu.org/archive/html/qemu-devel/2022-09/msg00455.html v1 -> v2: Fix tweaking the flags (Alex). Keep the custom build rule for now. tests/tcg/x86_64/Makefile.target | 6 +- tests/tcg/x86_64/cross-modifying-code.c | 80 +++++++++++++++++++++++++ 2 files changed, 85 insertions(+), 1 deletion(-) create mode 100644 tests/tcg/x86_64/cross-modifying-code.c diff --git a/tests/tcg/x86_64/Makefile.target b/tests/tcg/x86_64/Makefile.t= arget index 6177fd845a..3d9bc3377b 100644 --- a/tests/tcg/x86_64/Makefile.target +++ b/tests/tcg/x86_64/Makefile.target @@ -10,6 +10,7 @@ include $(SRC_PATH)/tests/tcg/i386/Makefile.target =20 ifeq ($(filter %-linux-user, $(TARGET)),$(TARGET)) X86_64_TESTS +=3D vsyscall +X86_64_TESTS +=3D cross-modifying-code TESTS=3D$(MULTIARCH_TESTS) $(X86_64_TESTS) test-x86_64 else TESTS=3D$(MULTIARCH_TESTS) @@ -23,5 +24,8 @@ test-x86_64: LDFLAGS+=3D-lm -lc test-x86_64: test-i386.c test-i386.h test-i386-shift.h test-i386-muldiv.h $(CC) $(CFLAGS) $< -o $@ $(LDFLAGS) =20 -vsyscall: $(SRC_PATH)/tests/tcg/x86_64/vsyscall.c +%: $(SRC_PATH)/tests/tcg/x86_64/%.c $(CC) $(CFLAGS) $< -o $@ $(LDFLAGS) + +cross-modifying-code: CFLAGS+=3D-pthread +cross-modifying-code: LDFLAGS+=3D-pthread diff --git a/tests/tcg/x86_64/cross-modifying-code.c b/tests/tcg/x86_64/cro= ss-modifying-code.c new file mode 100644 index 0000000000..2704df6061 --- /dev/null +++ b/tests/tcg/x86_64/cross-modifying-code.c @@ -0,0 +1,80 @@ +/* + * Test patching code, running in one thread, from another thread. + * + * Intel SDM calls this "cross-modifying code" and recommends a special + * sequence, which requires both threads to cooperate. + * + * Linux kernel uses a different sequence that does not require cooperatio= n and + * involves patching the first byte with int3. + * + * Finally, there is user-mode software out there that simply uses atomics= , and + * that seems to be good enough in practice. Test that QEMU has no problems + * with this as well. + */ + +#include +#include +#include +#include + +void add1_or_nop(long *x); +asm(".pushsection .rwx,\"awx\",@progbits\n" + ".globl add1_or_nop\n" + /* addq $0x1,(%rdi) */ + "add1_or_nop: .byte 0x48, 0x83, 0x07, 0x01\n" + "ret\n" + ".popsection\n"); + +#define THREAD_WAIT 0 +#define THREAD_PATCH 1 +#define THREAD_STOP 2 + +static void *thread_func(void *arg) +{ + int val =3D 0x0026748d; /* nop */ + + while (true) { + switch (__atomic_load_n((int *)arg, __ATOMIC_SEQ_CST)) { + case THREAD_WAIT: + break; + case THREAD_PATCH: + val =3D __atomic_exchange_n((int *)&add1_or_nop, val, + __ATOMIC_SEQ_CST); + break; + case THREAD_STOP: + return NULL; + default: + assert(false); + __builtin_unreachable(); + } + } +} + +#define INITIAL 42 +#define COUNT 1000000 + +int main(void) +{ + int command =3D THREAD_WAIT; + pthread_t thread; + long x =3D 0; + int err; + int i; + + err =3D pthread_create(&thread, NULL, &thread_func, &command); + assert(err =3D=3D 0); + + __atomic_store_n(&command, THREAD_PATCH, __ATOMIC_SEQ_CST); + for (i =3D 0; i < COUNT; i++) { + add1_or_nop(&x); + } + __atomic_store_n(&command, THREAD_STOP, __ATOMIC_SEQ_CST); + + err =3D pthread_join(thread, NULL); + assert(err =3D=3D 0); + + assert(x >=3D INITIAL); + assert(x <=3D INITIAL + COUNT); + + return EXIT_SUCCESS; +} --=20 2.37.2