From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (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 A6E5C34E745 for ; Thu, 18 Jun 2026 17:45:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781804731; cv=none; b=cOYM7cX0c5ytQ5DYnd9J+pQ49gzGDSMzm24x53xIGiw5f/C/R8oV7lhMWr+I3xrCi+0w0NxzI7br0avYkIgDkNHoqr47Vc4dFvTl7+FPaKV+mK+QKv0CvGy7XAQF+0e57NO7oq24RwTHLLKtm+awWVTik7Sc8tz6JmcLg9Nc97M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781804731; c=relaxed/simple; bh=m5pvj+8tGIMz3iLaE/UwxVOqQKpK/b8xO4m+OH37j/c=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=UG0eBqphCXQ7R4JDHuI/ov6FTRnezcywIZZqYnmH2Y+D4jLW5nMoy8xxJTA9nbVvsoIVg5N7OSf7cn1kM/qXnpmSWS+vSdaX4dxopiCKdzQrFbxAdoQAtIPh64DF/WFlkPTID44lcRukV4cacMCMxo8HYPj/0fV8ia7ZI+l3Y18= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=PJZKoxXb; arc=none smtp.client-ip=209.85.215.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="PJZKoxXb" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-c85798977dcso802055a12.0 for ; Thu, 18 Jun 2026 10:45:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1781804729; x=1782409529; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:reply-to:from:to:cc :subject:date:message-id:reply-to; bh=/+p6AYO/O72iLrHaDg8Gif1AlfgwEyWPAis8nfEYO7c=; b=PJZKoxXbEZ70npiJS7Msy1g65Gr8AkE7ood0TngxTHimtY6N42EFo27zLz/0aROr/z h6tNfIFpJroTlTRDrl7f/8zCnMyE6P99hXGGV8t31rnDMU50mPr0r+jXb5E4JXVcKJY9 ay6MnJtBu0pQeYszw+Gr82VbwSayKqKiYgxoFdcuaU4eUR6TPpqQtPgI6IvPiZRYBjFD df5w4L8zVMw+YeogouVZDbV4D2ZxMpFr7fRKlxzRfLZkCGLorpOWOHIlCSnBv/gCxBER y9WEvj1bnwDDJWyaD3TEae0R6HyO5cZM58EJi6U8L5fU2/EpEi/3INUAGowhRCR/uX03 hGSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781804729; x=1782409529; h=cc:to:from:subject:message-id:mime-version:date:reply-to :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=/+p6AYO/O72iLrHaDg8Gif1AlfgwEyWPAis8nfEYO7c=; b=QHHqzCqJ91wCi6Kx4YYV7X+y2T308Odj5OMbS+pShdDc5BzNqB9QORdb9rsY7d5F/X ZDDw8rWy5L70ogTVzZjTF1zU9q/yQTrqrjr1giiCqrkRBf2t5hDEkQO3XB854SXdbYze 6Y1z0rWF5Xk6uwDezKNffB02ZSe7MDj38iOWooJAYekn8cor1amcC5y4WwpAQWZkvj04 qO4fJcKUDT8GmeEWcpv9Ln4P0wgBV5UgJktULzpeTMRPcE4uRfMVOi/YoXDjvF6JJ/3+ PkXPJ/dP0It8OoSh/cd4JjxZwiPcjPXgcqikHlCzHM5AdaNVH4rIPEEFUTdVnqlubNGO hNiQ== X-Forwarded-Encrypted: i=1; AFNElJ8dKiNlgWGFuqRX7FsT9BuB1Zzc/lmYAK6I+mhN/dhrY89g2iV7dIfEMDxAhFiBFs5mwjZWPeCEc6zpFug=@vger.kernel.org X-Gm-Message-State: AOJu0YzSS8Naca2IZaYDFfxNRR8YtkOmwv3tJVxw6w2Vx/NzrxqxXann uCgzbD8mw2G3FZL7DlPMclSkXNHERc8lSwnUA4PT5oeln3C3XB9HCsqPbTttgLSTgvILdDJxJJi cJkx6tA== X-Received: from pgcv2.prod.google.com ([2002:a05:6a02:5302:b0:c89:a67b:d71f]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:6d82:b0:3ba:cd5b:3dc8 with SMTP id adf61e73a8af0-3bb3564395cmr15159637.31.1781804728707; Thu, 18 Jun 2026 10:45:28 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 18 Jun 2026 10:45:27 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.55.0.rc0.738.g0c8ab3ebcc-goog Message-ID: <20260618174527.1982333-1-seanjc@google.com> Subject: [PATCH] KVM: x86: WARN (once) if RTC pending EOI tracking goes off the rails From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" WARN once if KVM's tracking for pending EOIs for Real-Time Clock IRQs goes off the rails, as there's no reason to bug the host or risk a DoS due to spamming dmesg with endless WARNs. Absolute worst case scenario, guest time will go awry. Signed-off-by: Sean Christopherson --- arch/x86/kvm/ioapic.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c index f3f4a483ca15..34be1f0c76b3 100644 --- a/arch/x86/kvm/ioapic.c +++ b/arch/x86/kvm/ioapic.c @@ -84,7 +84,7 @@ static void kvm_rtc_eoi_tracking_restore_all(struct kvm_ioapic *ioapic); static void rtc_status_pending_eoi_check_valid(struct kvm_ioapic *ioapic) { - if (WARN_ON(ioapic->rtc_status.pending_eoi < 0)) + if (WARN_ON_ONCE(ioapic->rtc_status.pending_eoi < 0)) kvm_rtc_eoi_tracking_restore_all(ioapic); } @@ -484,7 +484,7 @@ static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status) * ensures that it is only called if it is >= zero, namely * if rtc_irq_check_coalesced returns false). */ - BUG_ON(ioapic->rtc_status.pending_eoi != 0); + WARN_ON_ONCE(ioapic->rtc_status.pending_eoi); ret = __kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, &ioapic->rtc_status); ioapic->rtc_status.pending_eoi = (ret < 0 ? 0 : ret); base-commit: 9d4853b044beefa21c4ee3e18c40653601a64ced -- 2.55.0.rc0.738.g0c8ab3ebcc-goog