From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 B0381198E63 for ; Tue, 19 Nov 2024 11:18:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732015106; cv=none; b=t0LBJZtsXu+mJ6Ah0d9LEAuwC8QxdCWQNV7vpow82WYk5YfO4glGwCKluT4qnzZu+9o0+nsXoZEnVvmCH5i/jbikkR6B56i+gbA5Upe4WqmMENIq3rB2Qbj53mFmbgJo0zLsK9kk26u3DEW92KdYaBkyA4/ZTnRHAcGwVFmfclk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732015106; c=relaxed/simple; bh=wLngPFSkyiBGIpyLXieAkQOBUSvIOcUzw8WGpXi5yNE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=e9XCKfUS0tNLI+pIcpeZvhL6PCMsi3plLesTjfdAPBrguPC+4u+NMCj8guE8Dt4RLWs1cQ7u+ing8oqu661LMHFhKJIlbVPkMDDoExXEzTjIVA/qT/pQu3eEqPheVjTK+s8cl1FlzFqhAfcWdaiyXGWKHaFhV7qRElwn24YpiKI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=HnX/Tpub; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="HnX/Tpub" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=RLrVQiNcfMB6d3HKCa0XFl/nEeJK7JxRTEXtm8stgQM=; b=HnX/TpubVPKXqtLNJstOQoUWyK Sk50h5rBTOqotY7wGVm+iHepeYRimFIDRpo+LVeeBfbfytFot6YpH86qBlDGlZQwFyli78rQETpLE vDk3lhP9QG44UUYbQrDSzH0Dz1YvsUSb38X4xrITutBmwASzjInI+osz3Bw0NCXRVAS4vi661aR2h uL9YILidQfXM+oFZhUjcwW4B6jrnzcaru3nqGAU/JJAYuj0oJSQj4QOW18ZYBCe5oRs5Gz+FGRPZq MFf6aNRCJtKgiq8fyFP7HBbQoekvDTRP609+NOgaxSSgPVZWVrFvROcpF4nh+gFleJjdFUXGlfuEO ZRchVZJQ==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tDMFG-00000000L0n-2zQj; Tue, 19 Nov 2024 11:18:10 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id C7E5A3006AB; Tue, 19 Nov 2024 12:18:09 +0100 (CET) Date: Tue, 19 Nov 2024 12:18:09 +0100 From: Peter Zijlstra To: Vadim Fedorenko Cc: Borislav Petkov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Thomas Gleixner , Yonghong Song , Vadim Fedorenko , Mykola Lysenko , x86@kernel.org, bpf@vger.kernel.org, Martin KaFai Lau Subject: Re: [PATCH bpf-next v7 1/4] bpf: add bpf_get_cpu_cycles kfunc Message-ID: <20241119111809.GB2328@noisy.programming.kicks-ass.net> References: <20241118185245.1065000-1-vadfed@meta.com> <20241118185245.1065000-2-vadfed@meta.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241118185245.1065000-2-vadfed@meta.com> On Mon, Nov 18, 2024 at 10:52:42AM -0800, Vadim Fedorenko wrote: > @@ -2094,6 +2094,13 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, > if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) { > int err; > > + if (imm32 == BPF_CALL_IMM(bpf_get_cpu_cycles)) { > + if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC)) > + EMIT3(0x0F, 0xAE, 0xE8); > + EMIT2(0x0F, 0x31); > + break; > + } TSC != cycles. Naming is bad.