From patchwork Sat Oct 19 17:15:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 13842850 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5F85BD3C926 for ; Sat, 19 Oct 2024 17:28:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:To:From:Reply-To: Cc:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=vTAIca6OWIHZqIV5zkcYiIX049iY2C2rvZwWFBzzqXk=; b=rHMg4tKbqwRErF4VbKgqT/QAT9 z7Jh08HV+xiWZqj4uE1KBMVt/CVxo//uRKr69SDIr1/LthO4Olkk6WbKtfTy1rJuPOj2vpVOcbEFD 83RiCZs9P5MWzFGOklS9TNEZ20znveT6FxnrDjallEFb1XaKokGoLaciuKJCfcYTzR4f5IzuzagTi lHPHv0DLji5eFH2W9Lo02yutcWnkTZrfXFF9W52cZG8XjK6rdXFYJmxkUiZrfJC64CZ/roChl76vu 3bGpSAutv0rP98ZJ/QrHXCArAK6JyCSR9GFeQceGY5s5IZiIE/6fXwBNRVAVhTGYCQds9K/h96i6X P/2qCj5A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t2DFL-00000003gYP-10mv; Sat, 19 Oct 2024 17:28:11 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t2DCP-00000003fce-3C9U for linux-arm-kernel@bombadil.infradead.org; Sat, 19 Oct 2024 17:25:09 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=vTAIca6OWIHZqIV5zkcYiIX049iY2C2rvZwWFBzzqXk=; b=KbYqWh6B6/tV7J8E6gZku4awnB VYxa0x88AZO0VUx6yOwrH8pVtZDljzv3l3CymQeE1zFA5U7xUdQJbLrPS3sdtIOfowrUCvoea9olQ qTdENZgRvcQ4OsxSmvuPlK6gOLDWkvKrGsDSrLT+Orkr8JSx265HIuNPrlhb/7SWjjIKln0w+53+y Ti6SaYtG+Q8PxAuzCv3RcVxRBuVbOXYkcDOlPw7BV2R22tfYGMvpSvDDZs1XEJXkS/5DDRTXkNX4q jSGPBM35JMijdXMjHhmSIVApy9Zg8XcquDI6UFaHkMX4dYIWQYIS7T2VFmDKw8CopawB0LnXOilgH t8+oa1LQ==; Received: from [2001:8b0:10b:1::ebe] (helo=i7.infradead.org) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1t2DCL-0000000EUis-0CMQ; Sat, 19 Oct 2024 17:25:07 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1t2DCI-00000009TKf-3LDy; Sat, 19 Oct 2024 18:25:02 +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, Francesco Lavra , Miguel Luis Subject: [PATCH v6 2/6] KVM: arm64: Add PSCI v1.3 SYSTEM_OFF2 function for hibernation Date: Sat, 19 Oct 2024 18:15:43 +0100 Message-ID: <20241019172459.2241939-3-dwmw2@infradead.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20241019172459.2241939-1-dwmw2@infradead.org> References: <20241019172459.2241939-1-dwmw2@infradead.org> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: David Woodhouse The PSCI v1.3 specification 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). This feature is safe to enable unconditionally (in a subsequent commit) because it is exposed to userspace through the existing KVM_SYSTEM_EVENT_SHUTDOWN event, just with an additional flag which userspace can use to know that the instance intended hibernation instead of a plain power-off. As with SYSTEM_RESET2, there is only one type available (in this case HIBERNATE_OFF), and it is not explicitly reported to userspace through the event; userspace can get it from the registers if it cares). Signed-off-by: David Woodhouse Reviewed-by: Miguel Luis --- Documentation/virt/kvm/api.rst | 11 ++++++++ arch/arm64/include/uapi/asm/kvm.h | 6 +++++ arch/arm64/kvm/psci.c | 44 +++++++++++++++++++++++++++++++ 3 files changed, 61 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index e32471977d0a..1ec076d806e6 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6855,6 +6855,10 @@ 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. @@ -6888,6 +6892,13 @@ 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..df834f2e928e 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 = PSCI_1_3_OFF_TYPE_HIBERNATE_OFF; + break; } break; case PSCI_1_0_FN_SYSTEM_SUSPEND: @@ -392,6 +403,39 @@ 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); + /* + * PSCI v1.3 issue F.b requires that zero be accepted to mean + * HIBERNATE_OFF (in line with pre-publication versions of the + * spec, and thus some actual implementations in the wild). + * The second argument must be zero. + */ + if ((arg && arg != PSCI_1_3_OFF_TYPE_HIBERNATE_OFF) || + smccc_get_arg2(vcpu) != 0) { + 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); }