From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f181.google.com (mail-pg1-f181.google.com [209.85.215.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3FBFF3D47B3 for ; Tue, 25 Aug 2026 08:37:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787647066; cv=none; b=cCmt6JDP8Ptv8+x61vx4Y201CTPclLB2IYATDZTrvMHlvhgter1P1hAKulfiyHDDNtPNOgb2m+ELz8IEQ4YX6sk4mO1quFCMKdXqyj1mCdTQOEOSRua3W0sRWaOoasswcaMrM/GPp5rMIJ2NlutPD4DT0r0Ygyq2zbO4e6dkiUY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787647066; c=relaxed/simple; bh=0iAVbxJH3sBm1IgSAaYTJfu2cuy78yxvo5wsLfXwV28=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OG3mRFzu0D1m586gEt15P+MO5E8m2lGiiimvH1Y3xvp0ibTsL9gJudmX3cz12+W/W1CKrKW/35oEC1XCWILbiEvWZTJIIPM3YtWqBUssJ56CuQeeI2eUjILkFhr5aVvS5TlmGATMzSwkgmlVTpZtWYFAJORjsaX46tNkUbXrlJw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=pOiMVnoM; arc=none smtp.client-ip=209.85.215.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="pOiMVnoM" Received: by mail-pg1-f181.google.com with SMTP id 41be03b00d2f7-c999f162c9aso3218716a12.3 for ; Tue, 25 Aug 2026 01:37:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787647065; x=1788251865; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=EKUnc+hCH/m96lQyJ3IHIfrh5f9TDgQ6D60NAJmR+nI=; b=pOiMVnoMgnKWz08lKUBi1dzlFZM0rCoBbT6G4hXhEgjAulrKXgFKIWD/eiQScfuBhW NTWpObtorNCgrGijogsplP9wvEqWNn/s8fjdNO8eq9bs+vD1T4q7DiRL2LjLzdi9xjGj 54Ar64QqzuBjLvgRvV//dn4qCk69fVuG+40ih0O57FwEmvcVcuikFvo/J3JWFnoshP0z W/Mw6+SC3L/2eyjpeePQPScMzESxlhZLrk+K4yEVJPcGMy+9BtGkv+klCBnDIIxc2Q5I Fm1GXH33Cyh9cJgfVgyfZoroFJYqDBwCRXKtUNv/VoyDoqbZtrjrM08LzSTRvoJ6IVTp Bv6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787647065; x=1788251865; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=EKUnc+hCH/m96lQyJ3IHIfrh5f9TDgQ6D60NAJmR+nI=; b=bwse6Rh+PHs/8TFfNF6QMQdA/N2btdv4KShOWpOqiuajaORPZqJa7fcDEvg5QHTcoV DVMOOxNwrD1Q/DoFzVj9rpkDYCsxph41ss910lI/j6Ds/wmzVfZ7Z1aW1b9mTgIvrFzJ BCWetGaz6PrwjjhqB28eMs9dst4VGTdUQL9O8hip2VoiOy5Hw8BQ+wKGayvSifIr79TT UMfklab6a7u7BS12IQKCkYedagjXvaFbcpNJbJvGXsYORo685cv2WixI2gHatFcBRLia bPTsMIC4VjlS6YX1eJ4YUShdOLpW48HNPwUyRWwdGrOQ5MxRJLcAu7sbeoZGHH68SOiC VXew== X-Forwarded-Encrypted: i=1; AHgh+RoJBgf6UW/7U+D3VAqLQftlkuM7/xSGE5rI6idwJDrHNCjBWxzgM4thFfPorMJsN61aq1OOn7qYFeGhI20=@vger.kernel.org X-Gm-Message-State: AFuF++kJz31DCkv9MsRxULLF16S7C3DkObHg4xB+vV2uwVsID4UcrWZe w1a/o7PB6T5W0dFGpEwXj1rb429re7P8a7dXI9PUtY+Ues79wLDQtS/g X-Gm-Gg: AR+sD11ymnhF702ECGHcJmN/AjTRQ1YU2lVgBTi0wLmVb7U9s2Mh7SW1aw5xS50/skQ lJXqpYmi7bGL5kW6t5qx8alhb26OmEuRDcV002rrx0GNe7X/1kB6E+9kveSoaw+DG6flRxUxrPk kZ2exYawdILJyFP6mX2GNQkPAsaHU6eQyig+yuesFydxinr0PtYDTsxcrTrZFakliii1lZ48JTe QZrx8VmuK/q7gUhVRqNg6ydKUy7FI6VZSnuldSvDnWHpjjLZG8YMViRNKnqX2uyuAN679XIM05/ S58SlT/oXvRUYalxfOkCB/bERc+psBYUxS2ARCNZGP8OvMXIXxBgL4jsJ1pU5sUl0pLwXu8jDp+ wz9cCeabJpcjxbkpaMPn4kPUQPrFeE+dnuwHe3FrT1CgSjHGFKp51d/hQ9FbDjRiFVKI9iDQe+1 tnVFoHZvBgWzg2bR3xEUuShJwRes2ATRtDCW4HTvt9XROfmdfGmK4Xal73kSdQN7OB4WJ6AEHxp xdZXBLYS5xT X-Received: by 2002:a05:6a20:6f04:b0:3c4:1916:9d3c with SMTP id adf61e73a8af0-3cd301428ecmr16874917637.15.1787647064570; Tue, 25 Aug 2026 01:37:44 -0700 (PDT) Received: from fedora ([61.74.238.173]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-cc199e60abbsm1835887a12.23.2026.08.25.01.37.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Aug 2026 01:37:44 -0700 (PDT) From: SeungJu Cheon To: Anup Patel , Atish Patra Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Andrew Jones , kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Shuah Khan , linux-kernel-mentees@lists.linux.dev, me@brighamcampbell.com, SeungJu Cheon Subject: [PATCH v1 1/3] RISC-V: KVM: Preserve firmware counter value across stop/start Date: Tue, 25 Aug 2026 17:37:17 +0900 Message-ID: <20260825083719.643970-2-suunj1331@gmail.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260825083719.643970-1-suunj1331@gmail.com> References: <20260825083719.643970-1-suunj1331@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Firmware events accumulate in kvpmu->fw_event[].value while running, but counter stop only clears fw_event[].started without saving the value back to pmc->counter_val. A subsequent counter start without SBI_PMU_START_FLAG_SET_INIT_VALUE reloads the stale counter_val into fw_event[].value, losing all events counted so far. Save fw_event[].value into counter_val when actually stopping a running counter, and remove the now redundant synchronization from the snapshot path. Fixes: badc386869e2c ("RISC-V: KVM: Support firmware events") Signed-off-by: SeungJu Cheon --- arch/riscv/kvm/vcpu_pmu.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c index 2025b664961c..56dd5b1b2846 100644 --- a/arch/riscv/kvm/vcpu_pmu.c +++ b/arch/riscv/kvm/vcpu_pmu.c @@ -671,10 +671,12 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base, goto out; } - if (!kvpmu->fw_event[fevent_code].started) + if (!kvpmu->fw_event[fevent_code].started) { sbiret = SBI_ERR_ALREADY_STOPPED; - - kvpmu->fw_event[fevent_code].started = false; + } else { + kvpmu->fw_event[fevent_code].started = false; + pmc->counter_val = kvpmu->fw_event[fevent_code].value; + } } else if (pmc->perf_event) { if (pmc->started) { /* Stop counting the counter */ @@ -692,9 +694,7 @@ int kvm_riscv_vcpu_pmu_ctr_stop(struct kvm_vcpu *vcpu, unsigned long ctr_base, } if (snap_flag_set && !sbiret) { - if (pmc->cinfo.type == SBI_PMU_CTR_TYPE_FW) - pmc->counter_val = kvpmu->fw_event[fevent_code].value; - else if (pmc->perf_event) + if (pmc->perf_event) pmc->counter_val += perf_event_read_value(pmc->perf_event, &enabled, &running); /* -- 2.52.0