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[59.124.168.89]) by smtp.gmail.com with ESMTPSA id g21-20020a170902c39500b001e7b7a79340sm3166065plg.267.2024.04.17.00.45.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Apr 2024 00:45:33 -0700 (PDT) From: Yong-Xuan Wang To: linux-riscv@lists.infradead.org, kvm-riscv@lists.infradead.org Cc: greentime.hu@sifive.com, vincent.chen@sifive.com, Yong-Xuan Wang , Paul Walmsley , Palmer Dabbelt , Albert Ou Subject: [PATCH v2 0/2] RISCV: KVM: Avoid lock inversion in SBI_EXT_HSM_HART_START Date: Wed, 17 Apr 2024 15:45:24 +0800 Message-Id: <20240417074528.16506-1-yongxuan.wang@sifive.com> X-Mailer: git-send-email 2.17.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240417_004535_571581_B8DBAB15 X-CRM114-Status: UNSURE ( 7.78 ) X-CRM114-Notice: Please train this message. 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: , MIME-Version: 1.0 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Documentation/virt/kvm/locking.rst advises that kvm->lock should be acquired outside vcpu->mutex and kvm->srcu. However, when KVM/RISC-V handling SBI_EXT_HSM_HART_START, the lock ordering is vcpu->mutex, kvm->srcu then kvm->lock. The use of kvm->lock over there ensures that only one VCPU can update the reset context and call SBI_EXT_HSM_HART_START for the target VCPU simultaneously. This patchset divides it into 2 separate spinlock, and replace vcpu->power_off with vcpu->mp_state. --- v2: - rename the hsm_start_lock to mp_state_lock - replace vcpu->power_off with vcpu->mp_state in PATCH1 - add vcpu->reset_cntx_lock in PATCH2 Yong-Xuan Wang (2): RISCV: KVM: Introduce mp_state_lock to avoid lock inversion in SBI_EXT_HSM_HART_START RISCV: KVM: Introduce vcpu->reset_cntx_lock arch/riscv/include/asm/kvm_host.h | 8 +++- arch/riscv/kvm/vcpu.c | 62 ++++++++++++++++++++++++------- arch/riscv/kvm/vcpu_sbi.c | 7 +++- arch/riscv/kvm/vcpu_sbi_hsm.c | 26 +++++++++---- 4 files changed, 78 insertions(+), 25 deletions(-)