From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (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 405503191D3 for ; Thu, 6 Nov 2025 14:44:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762440264; cv=none; b=VX2wGe4mMInM2YQ3R/eB1VJjPRSkXe6l+JLbNDeFyErlDhW0uqPtinkw417vmVAf2TuSf5u7EaIr3FMbSb38MfdFj0L1RzxdZRdl/+q23frxM5b98Q2iku55qbquA/dxDoadmVkDI8yxBaAWJVedhrU03sXfeVZmalRWbmSLNVw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762440264; c=relaxed/simple; bh=ZEqN0UPvK3HCK09MSfR+qkub5GZsyBTz/VhtlYBy2S4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=saYhjrWea7W6G/SjS5JSMSShicACFiwDO5QaXk38H6pNNoCEjVbXLal640UTCFQOSD1wolAGLOktEWpFR9S6z45/4laFVuZA+LnBR5gfnHAn0b7+XVmwjGSYeG6Sj+2pJ2guS9Nhm6CpKlpIdW4bG/uAIiHsP7iBdyo9G4GBlBA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--tabba.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=OzT2nXNo; arc=none smtp.client-ip=209.85.128.73 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--tabba.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OzT2nXNo" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-471001b980eso8138845e9.1 for ; Thu, 06 Nov 2025 06:44:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1762440260; x=1763045060; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=hQotLZ7bYQhnw+F+e2EgZGDV56Lv1I3QeSzBHAS6ry4=; b=OzT2nXNoiczHLv3Hja5+2tkDEw9aakJ7ngnyb/0LREobCmG4cl0laQ5RHVhzfvbpaH VrIrVc4Tb/cgoFGfGkm+pSGeOn7EVj71JuUihriRKC107T1ExpOhfCSzAiNJ94t1W7Cz +bMRW+UguoWoD5NOcLiuER1BLaw5X6ORsRO8iIOvz4E2/hTCSkMcmnL5cZZ3hOVzB1fk KMjIDDLFNJN7PusZDk1zG+rYsvRue0YK1ahJ4b5B6VIaiw/dNV/sCNiaMuCK3PeE5g7U 7/urGaJNS6YFtm9E+MTqvImSEYao4tCTXWZuTugv6XgyX4KQ8q11WNrp1v8OWWxUo8rQ fcHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762440260; x=1763045060; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=hQotLZ7bYQhnw+F+e2EgZGDV56Lv1I3QeSzBHAS6ry4=; b=CYGHQTCetfSRNb6End3eW6bnHAbWCE6wk9pqwr90pzc+HmtKQ+finvF9G1fqjzDz9D mm9BLYFcYpOw1IrKvykypA3cWOCe1suT6urh7fVhhPR0y6w/NLsgFkspxRdH2yyCCk0b dFTeMFsRK94/vdMx6SPTSW2PunfTvPd/8NzLO0+wvGZ1+p/ZOZQ1ecI0jNfzGNyuI5Pr 3z1smgP7IKOnxeLAUInEvjxRAc8zLWPORz64/twHOrKzaOL9bnuGQxswLbxNELfj4pq4 bca89akwcmRn6j30KdRIBLC7Ie0aYcHJJC+Rgs85CY1zJmRFzsTDtcE6giDvzDKBdv3p Z3LA== X-Gm-Message-State: AOJu0Yy7aeUD3WW2OnId2WyJM/8qlS+Ilw6ENjp34ZvfhHIqgVa/TYRz lmvldIrcOMWjtL7Rm1E0Wh0RqPy2IP/YO4gnGnD7skRQx19YcKb/hXtF1IcTXc5EsaPG2lA0S1j QQxNtFeAnqGKkwXpJLda20LORddN1tziScMFOWz74dWJbMUT683UP8NKiQ50iEmIaDg64ukJTPY gfunaqRrKDrHp/JbXLgSgfPPrrWh8OXfg= X-Google-Smtp-Source: AGHT+IG54VtmRITeyRodrpFjnkmMn9aKcd2SfV26fNYyANDC22/WKNUNo00I7Z8tR3a3z6jTuMfxSnvpDw== X-Received: from wmfu16.prod.google.com ([2002:a05:600c:1390:b0:46f:aa50:d716]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:5291:b0:471:9da:5232 with SMTP id 5b1f17b1804b1-4775cdc8eb1mr74506725e9.15.1762440260497; Thu, 06 Nov 2025 06:44:20 -0800 (PST) Date: Thu, 6 Nov 2025 14:44:14 +0000 In-Reply-To: <20251106144418.2847443-1-tabba@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251106144418.2847443-1-tabba@google.com> X-Mailer: git-send-email 2.51.2.1041.gc1ab5b90ca-goog Message-ID: <20251106144418.2847443-3-tabba@google.com> Subject: [PATCH v2 2/5] KVM: arm64: Fix Trace Buffer trap polarity for protected VMs From: Fuad Tabba To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: maz@kernel.org, oliver.upton@linux.dev, will@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, vladimir.murzin@arm.com, tabba@google.com Content-Type: text/plain; charset="UTF-8" The E2TB bits in MDCR_EL2 control trapping of Trace Buffer system register accesses. These accesses are trapped to EL2 when the bits are clear. The trap initialization logic for protected VMs in pvm_init_traps_mdcr() had the polarity inverted. When a guest did not support the Trace Buffer feature, the code was setting E2TB. This incorrectly disabled the trap, potentially allowing a protected guest to access registers for a feature it was not given. Fix this by inverting the operation. Fixes: f50758260bff ("KVM: arm64: Group setting traps for protected VMs by control register") Signed-off-by: Fuad Tabba --- arch/arm64/kvm/hyp/nvhe/pkvm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 8d06a246dfd1..f6f8996c4f97 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -118,7 +118,7 @@ static void pvm_init_traps_mdcr(struct kvm_vcpu *vcpu) val |= MDCR_EL2_TTRF; if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceBuffer, IMP)) - val |= MDCR_EL2_E2TB_MASK; + val &= ~MDCR_EL2_E2TB_MASK; /* Trap Debug Communications Channel registers */ if (!kvm_has_feat(kvm, ID_AA64MMFR0_EL1, FGT, IMP)) -- 2.51.2.1041.gc1ab5b90ca-goog