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[88.187.86.199]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-42b53f0b60csm11769883f8f.22.2025.11.14.12.06.02 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 14 Nov 2025 12:06:02 -0800 (PST) From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Cc: Alexander Graf , qemu-arm@nongnu.org, Phil Dennis-Jordan , Paolo Bonzini , Richard Henderson , Peter Collingbourne , Cameron Esfahani , Mohamed Mediouni , Peter Maydell , Akihiko Odaki , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Roman Bolshakov , Mads Ynddal Subject: [PATCH v5 13/19] accel/hvf: Implement WFI without using pselect() Date: Fri, 14 Nov 2025 21:04:15 +0100 Message-ID: <20251114200422.4280-14-philmd@linaro.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251114200422.4280-1-philmd@linaro.org> References: <20251114200422.4280-1-philmd@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::442; envelope-from=philmd@linaro.org; helo=mail-wr1-x442.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Return to the main loop where we'll be waken again. This avoid a tricky race with signals introduced in commit 219c101fa7f ("Add HVF WFI handler"). Signed-off-by: Philippe Mathieu-Daudé Reviewed-by: Akihiko Odaki --- include/system/hvf_int.h | 1 - accel/hvf/hvf-accel-ops.c | 3 -- target/arm/hvf/hvf.c | 74 +++------------------------------------ 3 files changed, 5 insertions(+), 73 deletions(-) diff --git a/include/system/hvf_int.h b/include/system/hvf_int.h index d842d4b2b99..c8e407a1463 100644 --- a/include/system/hvf_int.h +++ b/include/system/hvf_int.h @@ -47,7 +47,6 @@ struct AccelCPUState { #ifdef __aarch64__ hv_vcpu_exit_t *exit; bool vtimer_masked; - sigset_t unblock_ipi_mask; bool guest_debug_enabled; #endif }; diff --git a/accel/hvf/hvf-accel-ops.c b/accel/hvf/hvf-accel-ops.c index bbb0b385fe9..5922eb02e70 100644 --- a/accel/hvf/hvf-accel-ops.c +++ b/accel/hvf/hvf-accel-ops.c @@ -134,9 +134,6 @@ static int hvf_init_vcpu(CPUState *cpu) sigact.sa_handler = dummy_signal; sigaction(SIG_IPI, &sigact, NULL); - pthread_sigmask(SIG_BLOCK, NULL, &cpu->accel->unblock_ipi_mask); - sigdelset(&cpu->accel->unblock_ipi_mask, SIG_IPI); - #ifdef __aarch64__ r = hv_vcpu_create(&cpu->accel->fd, (hv_vcpu_exit_t **)&cpu->accel->exit, NULL); diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c index 5e46e8bf4dd..51fd8c7175b 100644 --- a/target/arm/hvf/hvf.c +++ b/target/arm/hvf/hvf.c @@ -301,7 +301,7 @@ void hvf_arm_init_debug(void) #define TMR_CTL_IMASK (1 << 1) #define TMR_CTL_ISTATUS (1 << 2) -static void hvf_wfi(CPUState *cpu); +static int hvf_wfi(CPUState *cpu); static uint32_t chosen_ipa_bit_size; @@ -1703,81 +1703,17 @@ static uint64_t hvf_vtimer_val_raw(void) return mach_absolute_time() - hvf_state->vtimer_offset; } -static uint64_t hvf_vtimer_val(void) +static int hvf_wfi(CPUState *cpu) { - if (!runstate_is_running()) { - /* VM is paused, the vtimer value is in vtimer.vtimer_val */ - return vtimer.vtimer_val; - } - - return hvf_vtimer_val_raw(); -} - -static void hvf_wait_for_ipi(CPUState *cpu, struct timespec *ts) -{ - /* - * Use pselect to sleep so that other threads can IPI us while we're - * sleeping. - */ - qatomic_set_mb(&cpu->thread_kicked, false); - bql_unlock(); - pselect(0, 0, 0, 0, ts, &cpu->accel->unblock_ipi_mask); - bql_lock(); -} - -static void hvf_wfi(CPUState *cpu) -{ - ARMCPU *arm_cpu = ARM_CPU(cpu); - struct timespec ts; - hv_return_t r; - uint64_t ctl; - uint64_t cval; - int64_t ticks_to_sleep; - uint64_t seconds; - uint64_t nanos; - uint32_t cntfrq; - if (cpu_has_work(cpu)) { /* * Don't bother to go into our "low power state" if * we would just wake up immediately. */ - return; + return 0; } - r = hv_vcpu_get_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CTL_EL0, &ctl); - assert_hvf_ok(r); - - if (!(ctl & 1) || (ctl & 2)) { - /* Timer disabled or masked, just wait for an IPI. */ - hvf_wait_for_ipi(cpu, NULL); - return; - } - - r = hv_vcpu_get_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CVAL_EL0, &cval); - assert_hvf_ok(r); - - ticks_to_sleep = cval - hvf_vtimer_val(); - if (ticks_to_sleep < 0) { - return; - } - - cntfrq = gt_cntfrq_period_ns(arm_cpu); - seconds = muldiv64(ticks_to_sleep, cntfrq, NANOSECONDS_PER_SECOND); - ticks_to_sleep -= muldiv64(seconds, NANOSECONDS_PER_SECOND, cntfrq); - nanos = ticks_to_sleep * cntfrq; - - /* - * Don't sleep for less than the time a context switch would take, - * so that we can satisfy fast timer requests on the same CPU. - * Measurements on M1 show the sweet spot to be ~2ms. - */ - if (!seconds && nanos < (2 * SCALE_MS)) { - return; - } - - ts = (struct timespec) { seconds, nanos }; - hvf_wait_for_ipi(cpu, &ts); + return EXCP_HLT; } /* Must be called by the owning thread */ @@ -1967,7 +1903,7 @@ static int hvf_handle_exception(CPUState *cpu, hv_vcpu_exit_exception_t *excp) case EC_WFX_TRAP: advance_pc = true; if (!(syndrome & WFX_IS_WFE)) { - hvf_wfi(cpu); + ret = hvf_wfi(cpu); } break; case EC_AA64_HVC: -- 2.51.0