From nobody Wed Dec 17 16:11:42 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DDE863570DA; Wed, 17 Dec 2025 10:14:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765966491; cv=none; b=MNWjrpHa/Sta7rejmiqc41tvgSM/MJ49AlcpLRD0n7w62OXR9AZmV0fXEaYTZ7JOzur9WlJ52COjv4ex3471U3kFck16eJUpGN6xm6EVdvmozh1otWB1mICbhrAiXjoqzZkAkPi8YXNu6tfXXbjMKwljtHJ/zZ+DuJZwXTYCWbE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765966491; c=relaxed/simple; bh=0fhlaTJAFyCKnyXzb19kNWtcKq8YcW1DPlF4IcviOS8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HH8h4mwQ0+cbKUIQW25lG8PJ7K2V8Pq/7Z8ynlAL1FdZcZFlIUDmxJkVZNqPw+yY3vso+Q7c08H2+Slbje9iDfZmgXGV2saMW/xrxWLuIEDT86bAy9sgdyrKNasHcInqMH6/ivMD4RiV1nNu0+mhvRD3+J/YMWCzWxg6tapEuIk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6325D1691; Wed, 17 Dec 2025 02:14:42 -0800 (PST) Received: from e122027.arm.com (unknown [10.57.45.201]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A97943F73B; Wed, 17 Dec 2025 02:14:44 -0800 (PST) From: Steven Price To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Jean-Philippe Brucker , Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve , Steven Price Subject: [PATCH v12 38/46] arm64: RMI: Propagate number of breakpoints and watchpoints to userspace Date: Wed, 17 Dec 2025 10:11:15 +0000 Message-ID: <20251217101125.91098-39-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251217101125.91098-1-steven.price@arm.com> References: <20251217101125.91098-1-steven.price@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Jean-Philippe Brucker The RMM describes the maximum number of BPs/WPs available to the guest in the Feature Register 0. Propagate those numbers into ID_AA64DFR0_EL1, which is visible to userspace. A VMM needs this information in order to set up realm parameters. Signed-off-by: Jean-Philippe Brucker Signed-off-by: Steven Price Reviewed-by: Gavin Shan Reviewed-by: Suzuki K Poulose Reviewed-by: Joey Gouly --- arch/arm64/include/asm/kvm_rmi.h | 2 ++ arch/arm64/kvm/rmi.c | 22 ++++++++++++++++++++++ arch/arm64/kvm/sys_regs.c | 2 +- 3 files changed, 25 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/asm/kvm_= rmi.h index 82280c138935..f36d3c845836 100644 --- a/arch/arm64/include/asm/kvm_rmi.h +++ b/arch/arm64/include/asm/kvm_rmi.h @@ -89,6 +89,8 @@ void kvm_init_rmi(void); u32 kvm_realm_ipa_limit(void); u32 kvm_realm_vgic_nr_lr(void); =20 +u64 kvm_realm_reset_id_aa64dfr0_el1(const struct kvm_vcpu *vcpu, u64 val); + bool kvm_rmi_supports_sve(void); =20 int kvm_init_realm_vm(struct kvm *kvm); diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c index 1d26fd893caf..1c5257636ef1 100644 --- a/arch/arm64/kvm/rmi.c +++ b/arch/arm64/kvm/rmi.c @@ -92,6 +92,28 @@ u32 kvm_realm_vgic_nr_lr(void) return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_GICV3_NUM_LRS); } =20 +u64 kvm_realm_reset_id_aa64dfr0_el1(const struct kvm_vcpu *vcpu, u64 val) +{ + u32 bps =3D u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_BPS); + u32 wps =3D u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_WPS); + u32 ctx_cmps; + + if (!kvm_is_realm(vcpu->kvm)) + return val; + + /* Ensure CTX_CMPs is still valid */ + ctx_cmps =3D FIELD_GET(ID_AA64DFR0_EL1_CTX_CMPs, val); + ctx_cmps =3D min(bps, ctx_cmps); + + val &=3D ~(ID_AA64DFR0_EL1_BRPs_MASK | ID_AA64DFR0_EL1_WRPs_MASK | + ID_AA64DFR0_EL1_CTX_CMPs); + val |=3D FIELD_PREP(ID_AA64DFR0_EL1_BRPs_MASK, bps) | + FIELD_PREP(ID_AA64DFR0_EL1_WRPs_MASK, wps) | + FIELD_PREP(ID_AA64DFR0_EL1_CTX_CMPs, ctx_cmps); + + return val; +} + static int get_start_level(struct realm *realm) { /* diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index af641939a033..70b51b5cdea8 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2043,7 +2043,7 @@ static u64 sanitise_id_aa64dfr0_el1(const struct kvm_= vcpu *vcpu, u64 val) /* Hide BRBE from guests */ val &=3D ~ID_AA64DFR0_EL1_BRBE_MASK; =20 - return val; + return kvm_realm_reset_id_aa64dfr0_el1(vcpu, val); } =20 /* --=20 2.43.0