From patchwork Mon Dec 25 12:58:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guo Ren X-Patchwork-Id: 13504654 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F11AA5479F; Mon, 25 Dec 2023 12:59:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jEIOj0Et" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4605CC433C9; Mon, 25 Dec 2023 12:59:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1703509181; bh=eTLon+HIxwFMbvdezleTBTpFzqzzZBcJdHF+vuZfDLk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jEIOj0EtbPA5/QvSmWlPD9LzcwSuEHnkJ7E5jKdiCW2nsqGhk/EGY7sd4FOPjfkP5 W/DR9oFO2xUVZkLvoqISc4EgWMebHjhg+n2mVezvN0uwdYFGB2PfZfyzTZkdFB7Xgf 1HZyxM3+DuKCy8Euzc/wQ4gKAAo/5vsWey1tgNeyuWAm2JJ7h79rTe2F/QjR4+n9VA Zn9obPY4be/cIIcaaPFNAQPbhy6JH50OVLJucvd1nrTPXjmoPiN0bXCH9dcrhv2cVY QN2+sBLHZ6/N1gItlVGl9rfs3klk5J98L2+e+Sz45Nk81pHAUi/WnBTggDjs/D562M Yr5IemZ/2vcWw== From: guoren@kernel.org To: paul.walmsley@sifive.com, palmer@dabbelt.com, guoren@kernel.org, panqinglin2020@iscas.ac.cn, bjorn@rivosinc.com, conor.dooley@microchip.com, leobras@redhat.com, peterz@infradead.org, anup@brainfault.org, keescook@chromium.org, wuwei2016@iscas.ac.cn, xiaoguang.xing@sophgo.com, chao.wei@sophgo.com, unicorn_wang@outlook.com, uwu@icenowy.me, jszhang@kernel.org, wefu@redhat.com, atishp@atishpatra.org Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, Guo Ren Subject: [PATCH V12 08/14] riscv: qspinlock: Force virt_spin_lock for KVM guests Date: Mon, 25 Dec 2023 07:58:41 -0500 Message-Id: <20231225125847.2778638-9-guoren@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20231225125847.2778638-1-guoren@kernel.org> References: <20231225125847.2778638-1-guoren@kernel.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Guo Ren Force to enable virt_spin_lock when KVM guest, because fair locks have horrible lock 'holder' preemption issues. Suggested-by: Leonardo Bras Link: https://lkml.kernel.org/kvm/ZQK9-tn2MepXlY1u@redhat.com/ Signed-off-by: Guo Ren Signed-off-by: Guo Ren Reviewed-by: Leonardo Bras --- arch/riscv/include/asm/sbi.h | 8 ++++++++ arch/riscv/kernel/sbi.c | 2 +- arch/riscv/kernel/setup.c | 6 +++++- 3 files changed, 14 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index 0892f4421bc4..8f748d9e1b85 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -51,6 +51,13 @@ enum sbi_ext_base_fid { SBI_EXT_BASE_GET_MIMPID, }; +enum sbi_ext_base_impl_id { + SBI_EXT_BASE_IMPL_ID_BBL = 0, + SBI_EXT_BASE_IMPL_ID_OPENSBI, + SBI_EXT_BASE_IMPL_ID_XVISOR, + SBI_EXT_BASE_IMPL_ID_KVM, +}; + enum sbi_ext_time_fid { SBI_EXT_TIME_SET_TIMER = 0, }; @@ -276,6 +283,7 @@ int sbi_console_getchar(void); long sbi_get_mvendorid(void); long sbi_get_marchid(void); long sbi_get_mimpid(void); +long sbi_get_firmware_id(void); void sbi_set_timer(uint64_t stime_value); void sbi_shutdown(void); void sbi_send_ipi(unsigned int cpu); diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 5a62ed1da453..4330aedf65fd 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -543,7 +543,7 @@ static inline long sbi_get_spec_version(void) return __sbi_base_ecall(SBI_EXT_BASE_GET_SPEC_VERSION); } -static inline long sbi_get_firmware_id(void) +long sbi_get_firmware_id(void) { return __sbi_base_ecall(SBI_EXT_BASE_GET_IMP_ID); } diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 0bafb9fd6ea3..e33430e9d97e 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -281,6 +281,9 @@ DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key); static void __init virt_spin_lock_init(void) { + if (sbi_get_firmware_id() != SBI_EXT_BASE_IMPL_ID_KVM) + no_virt_spin = true; + if (no_virt_spin) static_branch_disable(&virt_spin_lock_key); else @@ -290,7 +293,8 @@ static void __init virt_spin_lock_init(void) static void __init riscv_spinlock_init(void) { - if (!enable_qspinlock) { + if ((!enable_qspinlock) && + (sbi_get_firmware_id() != SBI_EXT_BASE_IMPL_ID_KVM)) { static_branch_disable(&combo_qspinlock_key); pr_info("Ticket spinlock: enabled\n"); } else {