From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-171.mta1.migadu.com (out-171.mta1.migadu.com [95.215.58.171]) (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 2163E20C489 for ; Fri, 23 May 2025 17:16:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748020584; cv=none; b=rkGzwuLdHGuRaW2Bd9yd7VCxkRprmwmGcoA5jRFXZ7Wh9fAxNR8MVuOD6cpMzK0ekgPjsEWbYYs4aO6hwXEmjKGYsK4/pQDRSvsus5eEh2sneRTrhHGxqDoTe23NAzUH+g2FWpGdxPhKLcKkKsrWT/pPVtP6zh00vRKcYfE/CAI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748020584; c=relaxed/simple; bh=Drp5lZRk4LA7SqjWH3KK6QjUHA5tD8wxZElSKSZPax4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Z0Q7oAppbqDp3ZkHxH5hTcwai1VwvY6A/uUNF2E+07oXLxNeuxT9B2ppPYQIaxqtk5twzwuf2KxvWD781hQxWDeU7snfZne5Y97JQmJyvlXk9AmlXVRXRmAUr6s+loNULzid3bO85dXAa/2qD5oaONXSo5oVMTicz74GOdQ0QXY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=p4ygCmn0; arc=none smtp.client-ip=95.215.58.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="p4ygCmn0" Message-ID: <61627296-6f94-45ea-9410-ed0ea2251870@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1748020578; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NwSnBgPFez8PLTovNHh7DO/HqAHVQL0w4mtppSLYja0=; b=p4ygCmn0/SgSUw/j+FUlcInOw5bcP3qQpAP+WTRtVHCq8zqDVxfsG3vreS7WCBAJhRjcTY CNS0wuI2Zor/NqLA6i4HP+ByVNwTy/KZWyPRvH4hhejZLNvTG/9jo7xnLQXl37V2+/wL9Q eok6kr9D3cEhlTaruAu9Wmz5VZIJWYI= Date: Fri, 23 May 2025 10:16:11 -0700 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v3 9/9] RISC-V: KVM: Upgrade the supported SBI version to 3.0 To: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Anup Patel , Will Deacon , Mark Rutland , Paul Walmsley , Palmer Dabbelt , Mayuresh Chitale Cc: linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Palmer Dabbelt , kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv References: <20250522-pmu_event_info-v3-0-f7bba7fd9cfe@rivosinc.com> <20250522-pmu_event_info-v3-9-f7bba7fd9cfe@rivosinc.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Atish Patra In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 5/23/25 6:31 AM, Radim Krčmář wrote: > 2025-05-22T12:03:43-07:00, Atish Patra : >> Upgrade the SBI version to v3.0 so that corresponding features >> can be enabled in the guest. >> >> Signed-off-by: Atish Patra >> --- >> diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h >> -#define KVM_SBI_VERSION_MAJOR 2 >> +#define KVM_SBI_VERSION_MAJOR 3 > I think it's time to add versioning to KVM SBI implementation. > Userspace should be able to select the desired SBI version and KVM would > tell the guest that newer features are not supported. We can achieve that through onereg interface by disabling individual SBI extensions. We can extend the existing onereg interface to disable a specific SBI version directly instead of individual ones to save those IOCTL as well. > We could somewhat get away with the userspace_sbi patch I posted, > because userspace would at least be in control of the SBI version, but > it would still be incorrect without a KVM enforcement, because a > misbehaving guest could use features that should not be supported.