From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-194.mta0.migadu.com (out-194.mta0.migadu.com [91.218.175.194]) (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 2FF2A3E48B for ; Tue, 3 Oct 2023 23:04:35 +0000 (UTC) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1696374273; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RURIJO+Ni1eJY5gvqmWqIxI0WRA6fE/M92fCnfYxFvo=; b=PJH3D8Uij5OdYF+r5ugobX1qqmHzY/C9MfxQSomWLM+qcLw1j4gy3I5OBp/Whb7rzqCHdP fRXY4o9XMS4YcpbwkBmHyv0H+lJPqKDikTlIXrK1XGN8pKhNh1vP8qW84zMVCot4BjghLN DMEKVlGJoKpKzkk5hlgH0M5kjRx1laY= From: Oliver Upton To: kvmarm@lists.linux.dev Cc: kvm@vger.kernel.org, Marc Zyngier , James Morse , Suzuki K Poulose , Zenghui Yu , Jing Zhang , Cornelia Huck , Oliver Upton Subject: [PATCH v11 08/12] KVM: arm64: Allow userspace to change ID_AA64PFR0_EL1 Date: Tue, 3 Oct 2023 23:04:04 +0000 Message-ID: <20231003230408.3405722-9-oliver.upton@linux.dev> In-Reply-To: <20231003230408.3405722-1-oliver.upton@linux.dev> References: <20231003230408.3405722-1-oliver.upton@linux.dev> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Jing Zhang Allow userspace to change the guest-visible value of the register with some severe limitation: - No changes to features not virtualized by KVM (AMU, MPAM, RAS) - Short of full GICv2 emulation in kernel, hiding GICv3 from the guest makes absolutely no sense. - FP is effectively assumed for KVM VMs. Signed-off-by: Jing Zhang [oliver: restrict features that are illogical to change] Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 9e31887ee0f4..24825b73d365 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2057,7 +2057,13 @@ static const struct sys_reg_desc sys_reg_descs[] = { .get_user = get_id_reg, .set_user = set_id_reg, .reset = read_sanitised_id_aa64pfr0_el1, - .val = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK, }, + .val = ~(ID_AA64PFR0_EL1_AMU | + ID_AA64PFR0_EL1_MPAM | + ID_AA64PFR0_EL1_SVE | + ID_AA64PFR0_EL1_RAS | + ID_AA64PFR0_EL1_GIC | + ID_AA64PFR0_EL1_AdvSIMD | + ID_AA64PFR0_EL1_FP), }, ID_SANITISED(ID_AA64PFR1_EL1), ID_UNALLOCATED(4,2), ID_UNALLOCATED(4,3), -- 2.42.0.609.gbb76f46606-goog