From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84AFB42C507; Fri, 31 Jul 2026 12:37:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785501479; cv=none; b=NpPwk66bZtk2AjGCWwfS7R6oWMbXmfdm3o1O5sf8LdQcIvkJWIA3UG3nP5auNNgZIUAtO3zCfgI6ZJrjoxGKDMkybdpQzi7NKgMFJLWndrtWeBSmzvkzSIC9BANg+YwkDjx+Q6ULlWtf5j0+w2S8n1RGAJDCoTPgrRGN1o1ymbg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785501479; c=relaxed/simple; bh=oWZdUmuK4nAtItYIMoZ1Nyc4/gTFqii47mmxgcveKIQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=G23IWCASynfNj6+KUE5VOpIMPWSMZCibaKJ/WC5+I7VT+T1w52RENyD9F3p2M1vlUwjz7aSPOh3GeM+ac01N+lMly7Dhv5zFlXg4JdSLwjS6+IIfFG+7sHpfnxTJPMtjjO2TQCFqDwMkaUnIhFjr1pVGhy6mTFds01ZIA6dR35I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=biHSZU6k; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="biHSZU6k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7ECB71F00A3D; Fri, 31 Jul 2026 12:37:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785501476; bh=P3e2rBRtLDRgrOIaI1elxNnJ/2QhoA9om1fNfFAW7Yo=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=biHSZU6kYX5v/wvxBwgrqds94+SRUsdrs9cFYmKK2XfdaaWDUHcf0EmH/451Xh9Qy 0gmqeXJQ3gaxq/yhEniHylXGmwSruAxDjLnNZdyLAvMj7L7Qn2Oq9iv2uHKCAp/8YI hLqIgCOAEo/E6WbmdYvHntzLnxUJc0Axhxf5a/RaauEKTRmODjOu4Eu4BxCccQiS4d JDg0BcjawbsF0LCKcQ7756qpooTFVYLgJ9Py+mEYwxue00ctkomE6fFiF0B9P5AyYq +Z/MeYLVKUs67p7UpkvgxiaIxeI9b6FR2pckj9k8oYQfdJnbTIMGzdYIjOdf1dnNWX gmsRmrbgJkAog== From: Mark Brown Date: Fri, 31 Jul 2026 13:25:46 +0100 Subject: [PATCH v17 08/14] KVM: arm64: Enforce EXLOCK for SPSR and ELR Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260731-arm64-gcs-v17-8-5e39ca01b14e@kernel.org> References: <20260731-arm64-gcs-v17-0-5e39ca01b14e@kernel.org> In-Reply-To: <20260731-arm64-gcs-v17-0-5e39ca01b14e@kernel.org> To: Catalin Marinas , Will Deacon , Marc Zyngier , Joey Gouly , Suzuki K Poulose , Shuah Khan , Fuad Tabba , Oliver Upton Cc: Peter Maydell , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Mark Brown X-Mailer: b4 0.16-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=3010; i=broonie@kernel.org; h=from:subject:message-id; bh=oWZdUmuK4nAtItYIMoZ1Nyc4/gTFqii47mmxgcveKIQ=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBqbJcCLPFgrfQ8svgEbiadv+hYFS4UMRXY1yBSB f+PnSAFLfqJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCamyXAgAKCRAk1otyXVSH 0HZbCACFJ9H+iuLy41JSKNoCVsfPYquTy02+GfUpVMKkTTYKxB+OUMC6X49vOrXNHgw4pyQuch2 gKjY9JNWIpqojyCMFmUKeHMcSHLxFf8X+6MQAn6r1V4wTT4I31KiLHYdlbkTjGMaE/NFldVmh7m IaTG9IgcDwxmgBQmID8dHquSjsKnMOeiGwemb/kQvFcnCMd5SMR9XvhhG3+Il/YHNqL0E+NRFTy 323bnRPy4jEhNj+/z71mFsC/r27M5NbLph+tMxF2IQ1AY+Y6Uor0MXouDBZaWrPu44LXgQE9M0J lOL+cqn/eRLorIGFfCzxhqfOSob2nRUmOiyDwOSWa2n1Hmi9 X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB As per I_CFFNS and the pseudocode for the SPSR_ELx and ELR_ELx registers a GCS exception with ExType 1 is generated for attempts to write to those registers when both GCSCR_ELx.EXLOCKEN and PSTATE.EXLOCK are set. Ensure that this is enforced for guests if access to these registers from the guest is handled by the hypervisor. Signed-off-by: Mark Brown --- arch/arm64/include/asm/kvm_emulate.h | 8 +++++++ arch/arm64/kvm/sys_regs.c | 42 ++++++++++++++++++++++++++++++++---- 2 files changed, 46 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index ee774c3b8dcd..bc012c86fcd6 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -81,6 +81,14 @@ int kvm_inject_nested_irq(struct kvm_vcpu *vcpu); int kvm_inject_nested_sea(struct kvm_vcpu *vcpu, bool iabt, u64 addr); int kvm_inject_nested_serror(struct kvm_vcpu *vcpu, u64 esr); +static inline void kvm_inject_exlock(struct kvm_vcpu *vcpu) +{ + u64 esr = FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_GCS) | ESR_ELx_IL | + FIELD_PREP(ESR_ELx_ExType_MASK, ESR_ELx_ExType_EXLOCK); + + kvm_inject_sync(vcpu, esr); +} + static inline void kvm_inject_nested_sve_trap(struct kvm_vcpu *vcpu) { u64 esr = FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_SVE) | diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 1a1e45d64552..3d9f4eb9d093 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2776,14 +2776,42 @@ static bool access_sp_el1(struct kvm_vcpu *vcpu, return true; } +static inline bool sysregs_exlocked(struct kvm_vcpu *vcpu) +{ + u64 gcscr; + + if (!kvm_has_gcs(vcpu->kvm)) + return false; + + if (!(vcpu->arch.ctxt.regs.pstate & PSR_EXLOCK_BIT)) + return false; + + /* + * Note that the EXLOCKEN for the running EL is checked + * regardless of the register written to. + */ + if (is_hyp_ctxt(vcpu)) + gcscr = vcpu_read_sys_reg(vcpu, GCSCR_EL2); + else + gcscr = vcpu_read_sys_reg(vcpu, GCSCR_EL1); + + return gcscr & GCSCR_ELx_EXLOCKEN; +} + static bool access_elr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { - if (p->is_write) + if (p->is_write) { + if (sysregs_exlocked(vcpu)) { + kvm_inject_exlock(vcpu); + return false; + } + vcpu_write_sys_reg(vcpu, p->regval, ELR_EL1); - else + } else { p->regval = vcpu_read_sys_reg(vcpu, ELR_EL1); + } return true; } @@ -2792,10 +2820,16 @@ static bool access_spsr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { - if (p->is_write) + if (p->is_write) { + if (sysregs_exlocked(vcpu)) { + kvm_inject_exlock(vcpu); + return false; + } + __vcpu_assign_sys_reg(vcpu, SPSR_EL1, p->regval); - else + } else { p->regval = __vcpu_sys_reg(vcpu, SPSR_EL1); + } return true; } -- 2.47.3