From patchwork Tue Sep 24 16:05:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 13811045 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 D2AEC1AD9F2; Tue, 24 Sep 2024 16:05:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727193937; cv=none; b=XewBYo07E9zLH1FkoKjkvyd9/2Qm2zEZz93rZoNNiGYR4a674pacnqrxZrMUFO2ZtBekqbbJ3Glf925AyCOxEVblAyAIJk+DTLxpLhcWOvsmveydeIuDpENz8VlYaQobhDR0WUv/NQGiqTx7lio3sQSGfTqD3eRG3hCPcq77iyA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727193937; c=relaxed/simple; bh=yhBC47VxMFMURrLgNn2H2pCVde/A1Z2RUJyvVL0nEaU=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tXOsxDGvk62u+CFAN0cOBWWsKmsTOgq2lfmGyv0NRZpYZt+a8Gc250GsvJhBM+P1MhuYwwtqDygtu6RSySH5f6uv8VGH++aVz6K7DsDT0QoCINi5QGnhptWrDlqrFMU0zzAKdKyu7tSs1XnMkTJzINsl1GyjiRr9TJ49P0TQrV0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=desiato.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=V/N5Rg3P; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=desiato.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="V/N5Rg3P" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:To:From:Reply-To: Cc:Content-Type:Content-ID:Content-Description; bh=VDRAzL7e2vQUFFjq+37YNHnN529VC0jgeD6HXShR8jg=; b=V/N5Rg3PY/NzhoEk9klBXJqfc4 6hvcEPGq122IpCSvqwrDL25pJi1So6CanRKOIKAu/oBem+IMT86aWBwneJPb7veLTWnPl5eQITTT2 srshfka80Tvok7NVQQoQmu4KyCkeDz2Khoms0181ky7YeVff0Z3SBkdTq/4W2h8qulGzsUxSa1iH1 +NvebaolXSyneOlRFH4Otxpqs5E3ooXK4VLvZqaB33YWqzaygW0GFVu/Gm0xPMS6f6MPqUteV1J1U zcmeUuRcJXqCqN1wG33fs6hpOjKbNAmp48bIj6tXfsFUD9jdY/E/vNFB6UNsviTQMlwDHHJSssQHt Aw7TA27Q==; Received: from [2001:8b0:10b:1::ebe] (helo=i7.infradead.org) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1st82M-00000001rIY-30sg; Tue, 24 Sep 2024 16:05:15 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1st82K-0000000HMiP-1bv5; Tue, 24 Sep 2024 17:05:12 +0100 From: David Woodhouse To: Paolo Bonzini , Jonathan Corbet , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Lorenzo Pieralisi , "Rafael J. Wysocki" , Pavel Machek , Len Brown , Shuah Khan , David Woodhouse , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-pm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v4 2/6] KVM: arm64: Add PSCI v1.3 SYSTEM_OFF2 function for hibernation Date: Tue, 24 Sep 2024 17:05:08 +0100 Message-ID: <20240924160512.4138879-2-dwmw2@infradead.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240924160512.4138879-1-dwmw2@infradead.org> References: <20240924160512.4138879-1-dwmw2@infradead.org> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by desiato.infradead.org. See http://www.infradead.org/rpr.html From: David Woodhouse The PSCI v1.3 specification (alpha) adds support for a SYSTEM_OFF2 function which is analogous to ACPI S4 state. This will allow hosting environments to determine that a guest is hibernated rather than just powered off, and ensure that they preserve the virtual environment appropriately to allow the guest to resume safely (or bump the hardware_signature in the FACS to trigger a clean reboot instead). The beta version will be changed to say that PSCI_FEATURES returns a bit mask of the supported hibernate types, which is implemented here. Although this new feature is inflicted unconditionally on unexpecting userspace, it ought to be mostly OK because it still results in the same KVM_SYSTEM_EVENT_SHUTDOWN event, just with a new flag which hopefully won't cause userspace to get unhappy. Signed-off-by: David Woodhouse --- Documentation/virt/kvm/api.rst | 11 +++++++++ arch/arm64/include/uapi/asm/kvm.h | 6 +++++ arch/arm64/kvm/psci.c | 37 +++++++++++++++++++++++++++++++ 3 files changed, 54 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index b3be87489108..2918898b7047 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6840,6 +6840,10 @@ the first `ndata` items (possibly zero) of the data array are valid. the guest issued a SYSTEM_RESET2 call according to v1.1 of the PSCI specification. + - for arm64, data[0] is set to KVM_SYSTEM_EVENT_SHUTDOWN_FLAG_PSCI_OFF2 + if the guest issued a SYSTEM_OFF2 call according to v1.3 of the PSCI + specification. + - for RISC-V, data[0] is set to the value of the second argument of the ``sbi_system_reset`` call. @@ -6873,6 +6877,13 @@ either: - Deny the guest request to suspend the VM. See ARM DEN0022D.b 5.19.2 "Caller responsibilities" for possible return values. +Hibernation using the PSCI SYSTEM_OFF2 call is enabled when PSCI v1.3 +is enabled. If a guest invokes the PSCI SYSTEM_OFF2 function, KVM will +exit to userspace with the KVM_SYSTEM_EVENT_SHUTDOWN event type and with +data[0] set to KVM_SYSTEM_EVENT_SHUTDOWN_FLAG_PSCI_OFF2. The only +supported hibernate type for the SYSTEM_OFF2 function is HIBERNATE_OFF +0x0). + :: /* KVM_EXIT_IOAPIC_EOI */ diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index 964df31da975..66736ff04011 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -484,6 +484,12 @@ enum { */ #define KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 (1ULL << 0) +/* + * Shutdown caused by a PSCI v1.3 SYSTEM_OFF2 call. + * Valid only when the system event has a type of KVM_SYSTEM_EVENT_SHUTDOWN. + */ +#define KVM_SYSTEM_EVENT_SHUTDOWN_FLAG_PSCI_OFF2 (1ULL << 0) + /* run->fail_entry.hardware_entry_failure_reason codes. */ #define KVM_EXIT_FAIL_ENTRY_CPU_UNSUPPORTED (1ULL << 0) diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c index 1f69b667332b..fd0f82464f7d 100644 --- a/arch/arm64/kvm/psci.c +++ b/arch/arm64/kvm/psci.c @@ -194,6 +194,12 @@ static void kvm_psci_system_off(struct kvm_vcpu *vcpu) kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN, 0); } +static void kvm_psci_system_off2(struct kvm_vcpu *vcpu) +{ + kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN, + KVM_SYSTEM_EVENT_SHUTDOWN_FLAG_PSCI_OFF2); +} + static void kvm_psci_system_reset(struct kvm_vcpu *vcpu) { kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET, 0); @@ -358,6 +364,11 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor) if (minor >= 1) val = 0; break; + case PSCI_1_3_FN_SYSTEM_OFF2: + case PSCI_1_3_FN64_SYSTEM_OFF2: + if (minor >= 3) + val = BIT(PSCI_1_3_HIBERNATE_TYPE_OFF); + break; } break; case PSCI_1_0_FN_SYSTEM_SUSPEND: @@ -392,6 +403,32 @@ static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor) break; } break; + case PSCI_1_3_FN_SYSTEM_OFF2: + kvm_psci_narrow_to_32bit(vcpu); + fallthrough; + case PSCI_1_3_FN64_SYSTEM_OFF2: + if (minor < 3) + break; + + arg = smccc_get_arg1(vcpu); + if (arg != PSCI_1_3_HIBERNATE_TYPE_OFF) { + val = PSCI_RET_INVALID_PARAMS; + break; + } + kvm_psci_system_off2(vcpu); + /* + * We shouldn't be going back to guest VCPU after + * receiving SYSTEM_OFF2 request. + * + * If user space accidentally/deliberately resumes + * guest VCPU after SYSTEM_OFF2 request then guest + * VCPU should see internal failure from PSCI return + * value. To achieve this, we preload r0 (or x0) with + * PSCI return value INTERNAL_FAILURE. + */ + val = PSCI_RET_INTERNAL_FAILURE; + ret = 0; + break; default: return kvm_psci_0_2_call(vcpu); }