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Wed, 16 Jul 2025 09:59:35 -0700 (PDT) From: Yury Norov To: Tianrui Zhao , Bibo Mao , Huacai Chen , WANG Xuerui , kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Cc: Yury Norov Subject: [PATCH 1/2] LoongArch: KVM: rework kvm_send_pv_ipi() Date: Wed, 16 Jul 2025 12:59:26 -0400 Message-ID: <20250716165929.22386-2-yury.norov@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250716165929.22386-1-yury.norov@gmail.com> References: <20250716165929.22386-1-yury.norov@gmail.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Yury Norov (NVIDIA)" The function in fact traverses a "bitmap" stored in GPR regs A1 and A2, but does it in a non-obvious way by creating a single-word bitmap twice. This patch switches the function to create a single 2-word bitmap, and also employs for_each_set_bit() macro, as it helps to drop most of housekeeping code. While there, convert the function to return void to not confuse readers with unchecked result. Signed-off-by: Yury Norov (NVIDIA) --- arch/loongarch/kvm/exit.c | 31 ++++++++++++------------------- 1 file changed, 12 insertions(+), 19 deletions(-) diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c index fa52251b3bf1..359afa909cee 100644 --- a/arch/loongarch/kvm/exit.c +++ b/arch/loongarch/kvm/exit.c @@ -821,32 +821,25 @@ static int kvm_handle_lbt_disabled(struct kvm_vcpu *vcpu, int ecode) return RESUME_GUEST; } -static int kvm_send_pv_ipi(struct kvm_vcpu *vcpu) +static void kvm_send_pv_ipi(struct kvm_vcpu *vcpu) { - unsigned int min, cpu, i; - unsigned long ipi_bitmap; + DECLARE_BITMAP(ipi_bitmap, BITS_PER_LONG * 2) = { + kvm_read_reg(vcpu, LOONGARCH_GPR_A1), + kvm_read_reg(vcpu, LOONGARCH_GPR_A2) + }; + unsigned int min, cpu; struct kvm_vcpu *dest; min = kvm_read_reg(vcpu, LOONGARCH_GPR_A3); - for (i = 0; i < 2; i++, min += BITS_PER_LONG) { - ipi_bitmap = kvm_read_reg(vcpu, LOONGARCH_GPR_A1 + i); - if (!ipi_bitmap) + for_each_set_bit(cpu, ipi_bitmap, BITS_PER_LONG * 2) { + dest = kvm_get_vcpu_by_cpuid(vcpu->kvm, cpu + min); + if (!dest) continue; - cpu = find_first_bit((void *)&ipi_bitmap, BITS_PER_LONG); - while (cpu < BITS_PER_LONG) { - dest = kvm_get_vcpu_by_cpuid(vcpu->kvm, cpu + min); - cpu = find_next_bit((void *)&ipi_bitmap, BITS_PER_LONG, cpu + 1); - if (!dest) - continue; - - /* Send SWI0 to dest vcpu to emulate IPI interrupt */ - kvm_queue_irq(dest, INT_SWI0); - kvm_vcpu_kick(dest); - } + /* Send SWI0 to dest vcpu to emulate IPI interrupt */ + kvm_queue_irq(dest, INT_SWI0); + kvm_vcpu_kick(dest); } - - return 0; } /* -- 2.43.0