From patchwork Sat Sep 14 10:17:28 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dapeng Mi X-Patchwork-Id: 13804297 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 682361D12EA; Sat, 14 Sep 2024 07:02:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.11 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726297323; cv=none; b=uUUNO/mIEbD4FVbIlgqZkaWyqSNZ9jiHkwbMn+lKNciX7vn8URXvcsMGusprsECuArTF02RTDEIRAdJaUu+5HFHYYF3jWHf1HU9QEZkgXMGMKdluo3auuT2NDr/zrWMAci32qcKXiMaJGsSmXzCrJXxi+9iQ3D2ol8lBgFV/XTk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726297323; c=relaxed/simple; bh=M4FmLtoUVjDaLJG+tUmv0c1pIfIWLYH5Bz71t6kstTk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=P97t05FJPfDA7sX3WBrcMmmv15EGnExirYin21siezJgvFIeYRu+uiAjKP6Y8BC5zYCQgD9Vr1hmdBTguHnRWLaeI85eEYBVIvyyVOAzf8kYwAghA0Q5lZD2NXep0kwEyWLHXGV+OzzcE5sOX9nBD6ZoZkTBWnNlCPmoB+OOUuI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=XK7UerGB; arc=none smtp.client-ip=198.175.65.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="XK7UerGB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1726297322; x=1757833322; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=M4FmLtoUVjDaLJG+tUmv0c1pIfIWLYH5Bz71t6kstTk=; b=XK7UerGBQWPJJq6U5+UUErH8aVe4yFiDko5YXGF5ZfnagahZMYyvJ2ZW GRVZEqZ8T4rPcSBdCU7/G4QeybRLSkebk+kJIAQTvnnEqqXyhdydj2bh8 l7qbmq/cp549v2xSnUd1rtihVIbQEf8xKf8q0I0lqV/eC/7T1mc7lBp++ GBdjTZ721qAZ39nnbzkZnbwt2Y+AmqgEavBNrM9HT+U5/rhYWyQLN5FEw CMyrO6mZzq8lbvXddCKWptbwNDQOT9IfNVIvluJfzrP1K/WZb5FOUro97 9utEJotSsm4wDZv+koYi6FebmCfyeVywcHDCKxuXBtBNC+OrV+Jav4uly w==; X-CSE-ConnectionGUID: uNThJpO9Rk2ecFFYHAsemQ== X-CSE-MsgGUID: LG8Msil4Tp2QgYOHPZNtwQ== X-IronPort-AV: E=McAfee;i="6700,10204,11194"; a="35778899" X-IronPort-AV: E=Sophos;i="6.10,228,1719903600"; d="scan'208";a="35778899" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Sep 2024 00:02:02 -0700 X-CSE-ConnectionGUID: TuQxA9nDRt+TpaV1XfE+6g== X-CSE-MsgGUID: FqI4piiFRryiZ6XGpGAoYA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,228,1719903600"; d="scan'208";a="67951026" Received: from emr.sh.intel.com ([10.112.229.56]) by fmviesa006.fm.intel.com with ESMTP; 14 Sep 2024 00:01:59 -0700 From: Dapeng Mi To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jim Mattson , Mingwei Zhang , Xiong Zhang , Zhenyu Wang , Like Xu , Jinrong Liang , Yongwei Ma , Dapeng Mi , Dapeng Mi Subject: [kvm-unit-tests patch v6 18/18] x86: pmu: Optimize emulated instruction validation Date: Sat, 14 Sep 2024 10:17:28 +0000 Message-Id: <20240914101728.33148-19-dapeng1.mi@linux.intel.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240914101728.33148-1-dapeng1.mi@linux.intel.com> References: <20240914101728.33148-1-dapeng1.mi@linux.intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 For support CPUs supporting PERF_GLOBAL_CTRL MSR, the validation for emulated instruction can be improved to check against precise counts for instructions and branches events instead of a rough range. Move enabling and disabling PERF_GLOBAL_CTRL MSR into kvm_fep_asm blob, thus instructions and branches events can be verified against precise counts. Signed-off-by: Dapeng Mi --- x86/pmu.c | 108 ++++++++++++++++++++++++++++++++---------------------- 1 file changed, 65 insertions(+), 43 deletions(-) diff --git a/x86/pmu.c b/x86/pmu.c index c7848fd1..3a5659b2 100644 --- a/x86/pmu.c +++ b/x86/pmu.c @@ -14,11 +14,6 @@ #define N 1000000 -// These values match the number of instructions and branches in the -// assembly block in check_emulated_instr(). -#define EXPECTED_INSTR 17 -#define EXPECTED_BRNCH 5 - #define IBPB_JMP_INSTRNS 9 #define IBPB_JMP_BRANCHES 2 @@ -71,6 +66,40 @@ do { \ : "edi"); \ } while (0) +/* the number of instructions and branches of the kvm_fep_asm() blob */ +#define KVM_FEP_INSTR 22 +#define KVM_FEP_BRNCH 5 + +/* + * KVM_FEP is a magic prefix that forces emulation so + * 'KVM_FEP "jne label\n"' just counts as a single instruction. + */ +#define kvm_fep_asm(_wrmsr) \ +do { \ + asm volatile( \ + _wrmsr "\n\t" \ + "mov %%ecx, %%edi;\n\t" \ + "mov $0x0, %%eax;\n\t" \ + "cmp $0x0, %%eax;\n\t" \ + KVM_FEP "jne 1f\n\t" \ + KVM_FEP "jne 1f\n\t" \ + KVM_FEP "jne 1f\n\t" \ + KVM_FEP "jne 1f\n\t" \ + KVM_FEP "jne 1f\n\t" \ + "mov $0xa, %%eax; cpuid;\n\t" \ + "mov $0xa, %%eax; cpuid;\n\t" \ + "mov $0xa, %%eax; cpuid;\n\t" \ + "mov $0xa, %%eax; cpuid;\n\t" \ + "mov $0xa, %%eax; cpuid;\n\t" \ + "1: mov %%edi, %%ecx; \n\t" \ + "xor %%eax, %%eax; \n\t" \ + "xor %%edx, %%edx;\n\t" \ + _wrmsr "\n\t" \ + : \ + : "a"(eax), "d"(edx), "c"(ecx) \ + : "ebx", "edi"); \ +} while (0) + typedef struct { uint32_t ctr; uint32_t idx; @@ -672,6 +701,7 @@ static void check_running_counter_wrmsr(void) static void check_emulated_instr(void) { + u32 eax, edx, ecx; uint64_t status, instr_start, brnch_start; uint64_t gp_counter_width = (1ull << pmu.gp_counter_width) - 1; unsigned int branch_idx = pmu.is_intel ? @@ -679,6 +709,7 @@ static void check_emulated_instr(void) unsigned int instruction_idx = pmu.is_intel ? INTEL_INSTRUCTIONS_IDX : AMD_INSTRUCTIONS_IDX; + pmu_counter_t brnch_cnt = { .ctr = MSR_GP_COUNTERx(0), /* branch instructions */ @@ -694,55 +725,46 @@ static void check_emulated_instr(void) if (this_cpu_has_perf_global_status()) pmu_clear_global_status(); - start_event(&brnch_cnt); - start_event(&instr_cnt); + __start_event(&brnch_cnt, 0); + __start_event(&instr_cnt, 0); - brnch_start = -EXPECTED_BRNCH; - instr_start = -EXPECTED_INSTR; + brnch_start = -KVM_FEP_BRNCH; + instr_start = -KVM_FEP_INSTR; wrmsr(MSR_GP_COUNTERx(0), brnch_start & gp_counter_width); wrmsr(MSR_GP_COUNTERx(1), instr_start & gp_counter_width); - // KVM_FEP is a magic prefix that forces emulation so - // 'KVM_FEP "jne label\n"' just counts as a single instruction. - asm volatile( - "mov $0x0, %%eax\n" - "cmp $0x0, %%eax\n" - KVM_FEP "jne label\n" - KVM_FEP "jne label\n" - KVM_FEP "jne label\n" - KVM_FEP "jne label\n" - KVM_FEP "jne label\n" - "mov $0xa, %%eax\n" - "cpuid\n" - "mov $0xa, %%eax\n" - "cpuid\n" - "mov $0xa, %%eax\n" - "cpuid\n" - "mov $0xa, %%eax\n" - "cpuid\n" - "mov $0xa, %%eax\n" - "cpuid\n" - "label:\n" - : - : - : "eax", "ebx", "ecx", "edx"); - if (this_cpu_has_perf_global_ctrl()) - wrmsr(pmu.msr_global_ctl, 0); + if (this_cpu_has_perf_global_ctrl()) { + eax = BIT(0) | BIT(1); + ecx = pmu.msr_global_ctl; + edx = 0; + kvm_fep_asm("wrmsr"); + } else { + eax = ecx = edx = 0; + kvm_fep_asm("nop"); + } - stop_event(&brnch_cnt); - stop_event(&instr_cnt); + __stop_event(&brnch_cnt); + __stop_event(&instr_cnt); // Check that the end count - start count is at least the expected // number of instructions and branches. - report(instr_cnt.count - instr_start >= EXPECTED_INSTR, - "instruction count"); - report(brnch_cnt.count - brnch_start >= EXPECTED_BRNCH, - "branch count"); + if (this_cpu_has_perf_global_ctrl()) { + report(instr_cnt.count - instr_start == KVM_FEP_INSTR, + "instruction count"); + report(brnch_cnt.count - brnch_start == KVM_FEP_BRNCH, + "branch count"); + } else { + report(instr_cnt.count - instr_start >= KVM_FEP_INSTR, + "instruction count"); + report(brnch_cnt.count - brnch_start >= KVM_FEP_BRNCH, + "branch count"); + } + if (this_cpu_has_perf_global_status()) { // Additionally check that those counters overflowed properly. status = rdmsr(pmu.msr_global_status); - report(status & 1, "branch counter overflow"); - report(status & 2, "instruction counter overflow"); + report(status & BIT_ULL(0), "branch counter overflow"); + report(status & BIT_ULL(1), "instruction counter overflow"); } report_prefix_pop();