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[24.4.73.83]) by smtp.gmail.com with ESMTPSA id w12-20020a1709027b8c00b0019a73a45e60sm6614676pll.19.2023.02.13.14.54.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Feb 2023 14:54:14 -0800 (PST) Message-ID: <82551518-7b7e-8ac9-7325-5d99d3be0406@rivosinc.com> Date: Mon, 13 Feb 2023 14:54:11 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH -next v13 10/19] riscv: Allocate user's vector context in the first-use trap Content-Language: en-US To: =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Andy Chiu , linux-riscv@lists.infradead.org, palmer@dabbelt.com, anup@brainfault.org, atishp@atishpatra.org, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org Cc: greentime.hu@sifive.com, guoren@linux.alibaba.com, Paul Walmsley , Albert Ou , Heiko Stuebner , Andrew Jones , Lad Prabhakar , Conor Dooley , Jisheng Zhang , Vincent Chen , Guo Ren , Li Zhengyu , Masahiro Yamada , Richard Henderson References: <20230125142056.18356-1-andy.chiu@sifive.com> <20230125142056.18356-11-andy.chiu@sifive.com> <875ycdy22c.fsf@all.your.base.are.belong.to.us> From: Vineet Gupta In-Reply-To: <875ycdy22c.fsf@all.your.base.are.belong.to.us> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2/7/23 06:36, Björn Töpel wrote: >> +bool rvv_first_use_handler(struct pt_regs *regs) >> +{ >> + __user u32 *epc = (u32 *)regs->epc; >> + u32 tval = (u32)regs->badaddr; >> + >> + /* If V has been enabled then it is not the first-use trap */ >> + if (vstate_query(regs)) >> + return false; >> + /* Get the instruction */ >> + if (!tval) { >> + if (__get_user(tval, epc)) >> + return false; >> + } >> + /* Filter out non-V instructions */ >> + if (!insn_is_vector(tval)) >> + return false; >> + /* Sanity check. datap should be null by the time of the first-use trap */ >> + WARN_ON(current->thread.vstate.datap); >> + /* >> + * Now we sure that this is a V instruction. And it executes in the >> + * context where VS has been off. So, try to allocate the user's V >> + * context and resume execution. >> + */ >> + if (rvv_thread_zalloc()) { >> + force_sig(SIGKILL); >> + return true; >> + } > Should the altstack size be taken into consideration, like x86 does in > validate_sigaltstack() (see __xstate_request_perm()). For a preexisting alternate stack ? Otherwise there is no "configuration" like x86 to cross-check against and V fault implies large'ish signal stack. See below as well. > Related; Would it make sense to implement sigaltstack_size_valid() for > riscv, analogous to x86? Indeed we need to do that for the case where alt stack is being setup, *after* V fault-on-first use. But how to handle an existing alt stack which might not be big enough to handle V state ? -Vineet From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4DD21C636D4 for ; Mon, 13 Feb 2023 22:54:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=M3u1GCEN3k126lJYR1ZK8l3p/4+VVwWIZZUtTAJ3JEE=; b=0rFr29L5l8Mq4X seZ2mq/HLx/IESAbwaunLIx3ExxrPP+9ZUAacrGSu+zbneoRTBXeeTkDDOUn81TYRzasQ5dIvdvXD godzF+pn7Js7/R4dtFPj7Q2APRGOUg5/sMmWwf67uCQNNJicJDbz7O6plOGZ1Z5KTaJv48Yqu60OP WjyBb6dCi4jn0NkraCVUwrgQNYwCLMM1lToTCPq5PZpodjTqRDx09v9yBcA/9I8eIMXGCr4pTLcRs ah3UhoU9H9N/XGvsF89m02TYsn18VfTZsRkwM2ue6lxpSVhEh8jXYk2mZRjcAX/Pr7vT4Lx63cwB6 LGsUQ+0m01YxRIlrt2/Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pRhiK-00GhFc-9m; Mon, 13 Feb 2023 22:54:24 +0000 Received: from mail-pl1-x634.google.com ([2607:f8b0:4864:20::634]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pRhiE-00GhDL-FF for linux-riscv@lists.infradead.org; Mon, 13 Feb 2023 22:54:19 +0000 Received: by mail-pl1-x634.google.com with SMTP id ja21so7566353plb.13 for ; Mon, 13 Feb 2023 14:54:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=522NNid6LgSf8RrS5VU4Hzm30KHabJK+kCnv1UqFDb0=; b=mtte59o9IYhPKzWfl/qT9tfiUcxy6kAiA6N3oEJ4/kDtAk6IHaeV8Ah3DKN7hi4djP roRG5azvNbUTt71U22BMRTRMmNjtGT0QUT/0tdhFIicPVCYnKF0k/w1B2pV25aPu+3Cc xUMDjVcRf+lrvAo0wJWWvjx12ohbRo9ajXkqJ2DACWfl3qX9m/8FuM8q0T22wHgnLcuW flpdu4daI+21oLgWczWmJyvsZ91Sg/s2YpEMpxHaSTqmc+fxgasIBV0DpnYorh76uUI+ uHXUhMsFbSRTnOc6toBJlfTYRj0iYDIAecWaIu1T+ldiRGVlf+WPl2Z9DWIsOIoBLp94 KRqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=522NNid6LgSf8RrS5VU4Hzm30KHabJK+kCnv1UqFDb0=; b=dBNjBmGVnzeLfhRP89TXFIAgqhdHpZPpowhPegiTCTvwsj77QQBYG7PdeaMyLPXaCF 2GFLdNcBXiEq1HU5+CXs85i0Khr9APsNtVFjm4mx3V+RJxai4n/kBQxS9CWPM985BI53 AXxAZvEtID6F+V6jE9loGO9YmYZ+DYgPhdEcFNDAPekZeQRMWD6l5pKXRUyNfg/LcAzE 6vLGgNgydFy1St5qp2oqjQEPqPMTqE8b2kzsrSy3vcWqJtL+98si6XDGh0DWSu8LEPbF uwa6KlaY92EMhllfx+YrDYUvzxGlteEfg5vmo9rZpVw/wVXPaXus6p7yxu1lW1stuf12 0eGA== X-Gm-Message-State: AO0yUKV5HNtay/gzw8STxG6SGIsH3b4woaQSFc/mo/fAnTyQSIUVsxs5 nMxsuOM59icQFF7gOm8kTO6ISw== X-Google-Smtp-Source: AK7set9pHsxVA/aZc7KMCzq2WCIjJ4lcMDk1bqdJg3wOOdIz4ZzT5DwjszXnvCGrpL0mXz+ckJW81w== X-Received: by 2002:a17:903:230a:b0:196:6162:1a76 with SMTP id d10-20020a170903230a00b0019661621a76mr709034plh.0.1676328854376; Mon, 13 Feb 2023 14:54:14 -0800 (PST) Received: from [192.168.50.116] (c-24-4-73-83.hsd1.ca.comcast.net. [24.4.73.83]) by smtp.gmail.com with ESMTPSA id w12-20020a1709027b8c00b0019a73a45e60sm6614676pll.19.2023.02.13.14.54.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Feb 2023 14:54:14 -0800 (PST) Message-ID: <82551518-7b7e-8ac9-7325-5d99d3be0406@rivosinc.com> Date: Mon, 13 Feb 2023 14:54:11 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH -next v13 10/19] riscv: Allocate user's vector context in the first-use trap Content-Language: en-US To: =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Andy Chiu , linux-riscv@lists.infradead.org, palmer@dabbelt.com, anup@brainfault.org, atishp@atishpatra.org, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org Cc: greentime.hu@sifive.com, guoren@linux.alibaba.com, Paul Walmsley , Albert Ou , Heiko Stuebner , Andrew Jones , Lad Prabhakar , Conor Dooley , Jisheng Zhang , Vincent Chen , Guo Ren , Li Zhengyu , Masahiro Yamada , Richard Henderson References: <20230125142056.18356-1-andy.chiu@sifive.com> <20230125142056.18356-11-andy.chiu@sifive.com> <875ycdy22c.fsf@all.your.base.are.belong.to.us> From: Vineet Gupta In-Reply-To: <875ycdy22c.fsf@all.your.base.are.belong.to.us> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230213_145418_515378_1F666247 X-CRM114-Status: GOOD ( 12.30 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org CgpPbiAyLzcvMjMgMDY6MzYsIEJqw7ZybiBUw7ZwZWwgd3JvdGU6Cj4+ICtib29sIHJ2dl9maXJz dF91c2VfaGFuZGxlcihzdHJ1Y3QgcHRfcmVncyAqcmVncykKPj4gK3sKPj4gKwlfX3VzZXIgdTMy ICplcGMgPSAodTMyICopcmVncy0+ZXBjOwo+PiArCXUzMiB0dmFsID0gKHUzMilyZWdzLT5iYWRh ZGRyOwo+PiArCj4+ICsJLyogSWYgViBoYXMgYmVlbiBlbmFibGVkIHRoZW4gaXQgaXMgbm90IHRo ZSBmaXJzdC11c2UgdHJhcCAqLwo+PiArCWlmICh2c3RhdGVfcXVlcnkocmVncykpCj4+ICsJCXJl dHVybiBmYWxzZTsKPj4gKwkvKiBHZXQgdGhlIGluc3RydWN0aW9uICovCj4+ICsJaWYgKCF0dmFs KSB7Cj4+ICsJCWlmIChfX2dldF91c2VyKHR2YWwsIGVwYykpCj4+ICsJCQlyZXR1cm4gZmFsc2U7 Cj4+ICsJfQo+PiArCS8qIEZpbHRlciBvdXQgbm9uLVYgaW5zdHJ1Y3Rpb25zICovCj4+ICsJaWYg KCFpbnNuX2lzX3ZlY3Rvcih0dmFsKSkKPj4gKwkJcmV0dXJuIGZhbHNlOwo+PiArCS8qIFNhbml0 eSBjaGVjay4gZGF0YXAgc2hvdWxkIGJlIG51bGwgYnkgdGhlIHRpbWUgb2YgdGhlIGZpcnN0LXVz ZSB0cmFwICovCj4+ICsJV0FSTl9PTihjdXJyZW50LT50aHJlYWQudnN0YXRlLmRhdGFwKTsKPj4g KwkvKgo+PiArCSAqIE5vdyB3ZSBzdXJlIHRoYXQgdGhpcyBpcyBhIFYgaW5zdHJ1Y3Rpb24uIEFu ZCBpdCBleGVjdXRlcyBpbiB0aGUKPj4gKwkgKiBjb250ZXh0IHdoZXJlIFZTIGhhcyBiZWVuIG9m Zi4gU28sIHRyeSB0byBhbGxvY2F0ZSB0aGUgdXNlcidzIFYKPj4gKwkgKiBjb250ZXh0IGFuZCBy ZXN1bWUgZXhlY3V0aW9uLgo+PiArCSAqLwo+PiArCWlmIChydnZfdGhyZWFkX3phbGxvYygpKSB7 Cj4+ICsJCWZvcmNlX3NpZyhTSUdLSUxMKTsKPj4gKwkJcmV0dXJuIHRydWU7Cj4+ICsJfQo+IFNo b3VsZCB0aGUgYWx0c3RhY2sgc2l6ZSBiZSB0YWtlbiBpbnRvIGNvbnNpZGVyYXRpb24sIGxpa2Ug eDg2IGRvZXMgaW4KPiB2YWxpZGF0ZV9zaWdhbHRzdGFjaygpIChzZWUgX194c3RhdGVfcmVxdWVz dF9wZXJtKCkpLgoKRm9yIGEgcHJlZXhpc3RpbmcgYWx0ZXJuYXRlIHN0YWNrID8gT3RoZXJ3aXNl IHRoZXJlIGlzIG5vIAoiY29uZmlndXJhdGlvbiIgbGlrZSB4ODYgdG8gY3Jvc3MtY2hlY2sgYWdh aW5zdCBhbmQgViBmYXVsdCBpbXBsaWVzIApsYXJnZSdpc2ggc2lnbmFsIHN0YWNrLgpTZWUgYmVs b3cgYXMgd2VsbC4KCj4gUmVsYXRlZDsgV291bGQgaXQgbWFrZSBzZW5zZSB0byBpbXBsZW1lbnQg c2lnYWx0c3RhY2tfc2l6ZV92YWxpZCgpIGZvcgo+IHJpc2N2LCBhbmFsb2dvdXMgdG8geDg2PwoK SW5kZWVkIHdlIG5lZWQgdG8gZG8gdGhhdCBmb3IgdGhlIGNhc2Ugd2hlcmUgYWx0IHN0YWNrIGlz IGJlaW5nIHNldHVwLCAKKmFmdGVyKiBWIGZhdWx0LW9uLWZpcnN0IHVzZS4KQnV0IGhvdyB0byBo YW5kbGUgYW4gZXhpc3RpbmcgYWx0IHN0YWNrIHdoaWNoIG1pZ2h0IG5vdCBiZSBiaWcgZW5vdWdo IHRvIApoYW5kbGUgViBzdGF0ZSA/CgotVmluZWV0CgpfX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fXwpsaW51eC1yaXNjdiBtYWlsaW5nIGxpc3QKbGludXgtcmlz Y3ZAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFkZWFkLm9yZy9tYWlsbWFu L2xpc3RpbmZvL2xpbnV4LXJpc2N2Cg==