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 77D91530DF0; Wed, 30 Sep 2026 21:49:24 +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=1790804965; cv=none; b=oHgQc7vuw3KkGPZwzWpgqrsRep0UzL8QTLzjt60SlDL7Me1kNf//qm4GaDVfssXr+o5mK21N1mfhld9dqEbfY7P/7FG/6wEjCJCVnlUAOdX2nXwdkFdoS+N7KPNkh28kgwzQ9VtUdH7SbFSmFhdak1PwYk5yn6mxuo8rGP5B1qU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790804965; c=relaxed/simple; bh=p2SMLjfEfZRBygQRA7fMdB/WEVVEAeNCJ7sGMUq/zOk=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=tueTaPLpJf3KWydXyThec05QtAzzZDcsP0OvRX73QKkvnAN7JlGV9WUJMQTpw6j8U3sZmDWLi5kI/2QJdgKrHkYhFyEiQr1W+/D5Szr0ulrKP9JEpg+ssPsNc2NbxUxUSV3HnTgQM0b4crJfONIM4tN1+Cg/tfO9tyDTL/blUV8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PoekURoQ; 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="PoekURoQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B70611F00898; Wed, 30 Sep 2026 21:49:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790804964; bh=Zd/+Jyw6bZX7UUcetdB7IGFu9m8nLhB6L7sX9bIi7t8=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=PoekURoQSMZiBIMi64huDTrJ8XyurMMyps4PwgX8Jhpg3Qox/1FqQldgWy/SBpDAy w/bVQNh9+cQ4vXg9WaBkr0bguVRE0vfQB5UUsbfh8yHjFDDUnyFKo9Vmr8M4MDPyUA anEC/wJx4K5PkR3bxoxobqenQV3dhJR58/TwMYrUony8jbyiVOBYm+psCYp+AIK2tX K+lVvMqQa8jZNBDCEXiBZ/ih2nPLB2bE88W8zQtlbe3U0DoxP37ZSEv8jGNDIjZMph BoDNpkcAYNLYclqMV6lWdYdWd/79chIw7twTJBXctKXCMyGv14EFnGD5Yhsgt+UK4U ++dttQ7HbmyQQ== From: Mark Brown Date: Wed, 30 Sep 2026 22:48:18 +0100 Subject: [PATCH v21 08/15] KVM: arm64: Enforce EXLOCK for SPSR and ELR Precedence: bulk X-Mailing-List: linux-kernel@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: <20260930-arm64-gcs-v21-8-3556644cd927@kernel.org> References: <20260930-arm64-gcs-v21-0-3556644cd927@kernel.org> In-Reply-To: <20260930-arm64-gcs-v21-0-3556644cd927@kernel.org> To: Catalin Marinas , Will Deacon , Marc Zyngier , Joey Gouly , Suzuki K Poulose , Shuah Khan , Oliver Upton , Fuad Tabba Cc: Peter Maydell , Leonardo Bras , Wei-Lin Chang , Yao Yuan , 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 0.17-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=3057; i=broonie@kernel.org; h=from:subject:message-id; bh=p2SMLjfEfZRBygQRA7fMdB/WEVVEAeNCJ7sGMUq/zOk=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBqvYO52fYAk0djW5voyppA7cUSGG3uVSRxOiiRx JhEDbivJR2JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCar2DuQAKCRAk1otyXVSH 0A47B/9vXV2XCZ6uLeUIFTwXHKySyUmCeMIABlrqUbh0HBy2DSdhuNhtCUJKVT+x5TEVGqHJZGz L12rQ9zN7WuGhDxeCCCC9mRC6Dwwuf3tBCd0w8JACxqvsnWKlOW5fPlyHfDfFxBRgeydVOc5dN0 aZcsRdyj1mmww5kjbPCXanopo0fgnvnEI1ktiHCJaa4HZvU74IfpUMP8PL4DhaO2R6/0kyT1D2s q29bZa69GL7Bya0uou1HKWKGm86gASDjo6aydBCBNLs26KAOnkO0uN1j4qtkfkm2EqsqYPn4IvU g9TD4cUe+5McxzCFL56ctMFXmnZYHub5lDZpCB+1oep2x4Je 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. Reviewed-by: Leonardo Bras 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 0cd91b3d6c82..e47ab38327de 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 823460106de8..faecf4657ec5 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2866,14 +2866,42 @@ 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; } @@ -2882,10 +2910,16 @@ 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