From nobody Mon Nov 25 04:58:37 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; 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 Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 17178053639661020.6073694429589; Fri, 7 Jun 2024 17:09:23 -0700 (PDT) Received: from [::1] (helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sFf5v-00056i-BI; Fri, 07 Jun 2024 15:17:47 -0400 Received: from [2001:470:142:3::10] (helo=eggs.gnu.org) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sFf5s-0004nL-3E; Fri, 07 Jun 2024 15:17:44 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sFf5q-00037y-7O; Fri, 07 Jun 2024 15:17:43 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id DF0886E56E; Fri, 7 Jun 2024 22:14:54 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id 232B4E2767; Fri, 7 Jun 2024 22:14:00 +0300 (MSK) Received: (nullmailer pid 529469 invoked by uid 1000); Fri, 07 Jun 2024 19:13:58 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Yong-Xuan Wang , Andrew Jones , Alistair Francis , Michael Tokarev Subject: [Stable-9.0.1 64/71] target/riscv/kvm.c: Fix the hart bit setting of AIA Date: Fri, 7 Jun 2024 22:13:45 +0300 Message-Id: <20240607191356.529336-20-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, 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-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1717805365224100001 Content-Type: text/plain; charset="utf-8" From: Yong-Xuan Wang In AIA spec, each hart (or each hart within a group) has a unique hart number to locate the memory pages of interrupt files in the address space. The number of bits required to represent any hart number is equal to ceil(log2(hmax + 1)), where hmax is the largest hart number among groups. However, if the largest hart number among groups is a power of 2, QEMU will pass an inaccurate hart-index-bit setting to Linux. For example, when the guest OS has 4 harts, only ceil(log2(3 + 1)) =3D 2 bits are sufficient to represent 4 harts, but we passes 3 to Linux. The code needs to be updated to ensure accurate hart-index-bit settings. Additionally, a Linux patch[1] is necessary to correctly recover the hart index when the guest OS has only 1 hart, where the hart-index-bit is 0. [1] https://lore.kernel.org/lkml/20240415064905.25184-1-yongxuan.wang@sifiv= e.com/t/ Signed-off-by: Yong-Xuan Wang Reviewed-by: Andrew Jones Cc: qemu-stable Message-ID: <20240515091129.28116-1-yongxuan.wang@sifive.com> Signed-off-by: Alistair Francis (cherry picked from commit 190b867f28cb5781f3cd01a3deb371e4211595b1) Signed-off-by: Michael Tokarev diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c index 5187b88ad9..94b0e393bf 100644 --- a/target/riscv/kvm/kvm-cpu.c +++ b/target/riscv/kvm/kvm-cpu.c @@ -1671,7 +1671,14 @@ void kvm_riscv_aia_create(MachineState *machine, uin= t64_t group_shift, } } =20 - hart_bits =3D find_last_bit(&max_hart_per_socket, BITS_PER_LONG) + 1; + + if (max_hart_per_socket > 1) { + max_hart_per_socket--; + hart_bits =3D find_last_bit(&max_hart_per_socket, BITS_PER_LONG) += 1; + } else { + hart_bits =3D 0; + } + ret =3D kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG, KVM_DEV_RISCV_AIA_CONFIG_HART_BITS, &hart_bits, true, NULL); --=20 2.39.2