From patchwork Tue Feb 22 06:47:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 12754588 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34E2AC433EF for ; Tue, 22 Feb 2022 06:47:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230295AbiBVGsG (ORCPT ); Tue, 22 Feb 2022 01:48:06 -0500 Received: from gmail-smtp-in.l.google.com ([23.128.96.19]:35294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230290AbiBVGsF (ORCPT ); Tue, 22 Feb 2022 01:48:05 -0500 Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A45910DA43 for ; Mon, 21 Feb 2022 22:47:40 -0800 (PST) Received: by mail-pl1-x62e.google.com with SMTP id q11so4971033pln.11 for ; Mon, 21 Feb 2022 22:47:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ckR48vt1cgkASlzMuOBw9/smoxoiL+0ygwyW1GVhHh0=; b=NgqPVGQ37kzGORW20RTW/yP/3WaOOpZLs9q/6q25V0myESaN8o2EpSjpNbKJtT7Abx UfaxwVr57DOKkd1JQn3KwqQg//2qmTtjibIdo25sBPzmk0zNg9Upz8DDI+DK9eUUHpHl XYTjuRTo6yk7UCNkqluiEnz398S35SKUfJ79e9Vaz8Y09G3S4OBC9DL024oAgiCbmz/i hc8S1JQsLWSFg7QXbKnx1XGOp38KGNM5LIDzna2ckoWfHAyw0vfdfaZqODImgIOCl25s JQGvE4kOQdDb9t8daWkIfMdpfRkXi8459mlJqAyR1sd+rFNQWvx3/ToumiEu2tamzL15 i5iQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ckR48vt1cgkASlzMuOBw9/smoxoiL+0ygwyW1GVhHh0=; b=H1iMBwmMTFZoTuyHvJrPyMO9022vgng7JlG4R/dTODjLClzJJ6EZFRkAGUXLi479tY XZk4bZ0HTtrly6w4iZTrKvNIGD6gUrtws4K0VkQNZrziRMUFLqr1rxLmx9G4kMwwcDZx e2E/vRs7YjMgp8yNgh3zYzY83FNnypJ/NOV0bvnGuhecn1MQehQew/eDuxtQpyy9Ylmk RBViAhXiOfcvjsb1KAW/S40aNiYUlg/XslPgwJ/Bn0cltldDttz40Akt50gMiJFOD788 SEfGmrr80MOPfZg8NdgtiB93lbDkwI/2/kexPXvK0bGs8Y445E6IaIWzX8QdRdHV9Y6N YNAA== X-Gm-Message-State: AOAM532ssjUN/zQzaquo4e1+1FvjUetGPZtn7h5huIMHETiCjyitzE+a JEiQg7YPSK5O5jWiVlQiKWA= X-Google-Smtp-Source: ABdhPJweu7hHQiEc3qCESh6QWPd6B4LvoxgbYZuuxbXhbw8sLl9LjDDzJCfgWVh4n9IY281MAW4F/A== X-Received: by 2002:a17:90b:3594:b0:1bc:7001:5203 with SMTP id mm20-20020a17090b359400b001bc70015203mr2098119pjb.84.1645512459578; Mon, 21 Feb 2022 22:47:39 -0800 (PST) Received: from bobo.ibm.com (193-116-225-41.tpgi.com.au. [193.116.225.41]) by smtp.gmail.com with ESMTPSA id d8sm16346711pfv.84.2022.02.21.22.47.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Feb 2022 22:47:39 -0800 (PST) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin , Paolo Bonzini , kvm@vger.kernel.org, Fabiano Rosas Subject: [PATCH v4 1/3] KVM: PPC: Book3S PR: Disable SCV when AIL could be disabled Date: Tue, 22 Feb 2022 16:47:25 +1000 Message-Id: <20220222064727.2314380-2-npiggin@gmail.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220222064727.2314380-1-npiggin@gmail.com> References: <20220222064727.2314380-1-npiggin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org PR KVM does not support running with AIL enabled, and SCV does is not supported with AIL disabled. Fix this by ensuring the SCV facility is disabled with FSCR while a CPU could be running with AIL=0. The PowerNV host supports disabling AIL on a per-CPU basis, so SCV just needs to be disabled when a vCPU is being run. The pSeries machine can only switch AIL on a system-wide basis, so it must disable SCV support at boot if the configuration can potentially run a PR KVM guest. Also ensure a the FSCR[SCV] bit can not be enabled when emulating mtFSCR for the guest. SCV is not emulated for the PR guest at the moment, this just fixes the host crashes. Alternatives considered and rejected: - SCV support can not be disabled by PR KVM after boot, because it is advertised to userspace with HWCAP. - AIL can not be disabled on a per-CPU basis. At least when running on pseries it is a per-LPAR setting. - Support for real-mode SCV vectors will not be added because they are at 0x17000 so making such a large fixed head space causes immediate value limits to be exceeded, requiring a lot rework and more code. - Disabling SCV for any PR KVM possible kernel will cause a slowdown when not using PR KVM. - A boot time option to disable SCV to use PR KVM is user-hostile. - System call instruction emulation for SCV facility unavailable instructions is too complex and old emulation code was subtly broken and removed. Reviewed-by: Fabiano Rosas Signed-off-by: Nicholas Piggin --- arch/powerpc/kernel/exceptions-64s.S | 4 ++++ arch/powerpc/kernel/setup_64.c | 28 ++++++++++++++++++++++++++++ arch/powerpc/kvm/Kconfig | 9 +++++++++ arch/powerpc/kvm/book3s_pr.c | 26 +++++++++++++++++--------- 4 files changed, 58 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 55caeee37c08..b66dd6f775a4 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -809,6 +809,10 @@ __start_interrupts: * - MSR_EE|MSR_RI is clear (no reentrant exceptions) * - Standard kernel environment is set up (stack, paca, etc) * + * KVM: + * These interrupts do not elevate HV 0->1, so HV is not involved. PR KVM + * ensures that FSCR[SCV] is disabled whenever it has to force AIL off. + * * Call convention: * * syscall register convention is in Documentation/powerpc/syscall64-abi.rst diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index be8577ac9397..d973ae7558e3 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -197,6 +197,34 @@ static void __init configure_exceptions(void) /* Under a PAPR hypervisor, we need hypercalls */ if (firmware_has_feature(FW_FEATURE_SET_MODE)) { + /* + * - PR KVM does not support AIL mode interrupts in the host + * while a PR guest is running. + * + * - SCV system call interrupt vectors are only implemented for + * AIL mode interrupts. + * + * - On pseries, AIL mode can only be enabled and disabled + * system-wide so when a PR VM is created on a pseries host, + * all CPUs of the host are set to AIL=0 mode. + * + * - Therefore host CPUs must not execute scv while a PR VM + * exists. + * + * - SCV support can not be disabled dynamically because the + * feature is advertised to host userspace. Disabling the + * facility and emulating it would be possible but is not + * implemented. + * + * - So SCV support is blanket disabled if PR KVM could possibly + * run. That is, PR support compiled in, booting on pseries + * with hash MMU. + */ + if (IS_ENABLED(CONFIG_KVM_BOOK3S_PR_POSSIBLE) && !radix_enabled()) { + init_task.thread.fscr &= ~FSCR_SCV; + cur_cpu_spec->cpu_user_features2 &= ~PPC_FEATURE2_SCV; + } + /* Enable AIL if possible */ if (!pseries_enable_reloc_on_exc()) { init_task.thread.fscr &= ~FSCR_SCV; diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig index 18e58085447c..ddd88179110a 100644 --- a/arch/powerpc/kvm/Kconfig +++ b/arch/powerpc/kvm/Kconfig @@ -112,12 +112,21 @@ config KVM_BOOK3S_64_PR guest in user mode (problem state) and emulating all privileged instructions and registers. + This is only available for hash MMU mode and only supports + guests that use hash MMU mode. + This is not as fast as using hypervisor mode, but works on machines where hypervisor mode is not available or not usable, and can emulate processors that are different from the host processor, including emulating 32-bit processors on a 64-bit host. + Selecting this option will cause the SCV facility to be + disabled when the kernel is booted on the pseries platform in + hash MMU mode (regardless of PR VMs running). When any PR VMs + are running, "AIL" mode is disabled which may slow interrupts + and system calls on the host. + config KVM_BOOK3S_HV_EXIT_TIMING bool "Detailed timing for hypervisor real-mode code" depends on KVM_BOOK3S_HV_POSSIBLE && DEBUG_FS diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 34a801c3604a..7bf9e6ca5c2d 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -137,12 +137,15 @@ static void kvmppc_core_vcpu_load_pr(struct kvm_vcpu *vcpu, int cpu) svcpu->slb_max = to_book3s(vcpu)->slb_shadow_max; svcpu->in_use = 0; svcpu_put(svcpu); -#endif /* Disable AIL if supported */ - if (cpu_has_feature(CPU_FTR_HVMODE) && - cpu_has_feature(CPU_FTR_ARCH_207S)) - mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~LPCR_AIL); + if (cpu_has_feature(CPU_FTR_HVMODE)) { + if (cpu_has_feature(CPU_FTR_ARCH_207S)) + mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~LPCR_AIL); + if (cpu_has_feature(CPU_FTR_ARCH_300) && (current->thread.fscr & FSCR_SCV)) + mtspr(SPRN_FSCR, mfspr(SPRN_FSCR) & ~FSCR_SCV); + } +#endif vcpu->cpu = smp_processor_id(); #ifdef CONFIG_PPC_BOOK3S_32 @@ -165,6 +168,14 @@ static void kvmppc_core_vcpu_put_pr(struct kvm_vcpu *vcpu) memcpy(to_book3s(vcpu)->slb_shadow, svcpu->slb, sizeof(svcpu->slb)); to_book3s(vcpu)->slb_shadow_max = svcpu->slb_max; svcpu_put(svcpu); + + /* Enable AIL if supported */ + if (cpu_has_feature(CPU_FTR_HVMODE)) { + if (cpu_has_feature(CPU_FTR_ARCH_207S)) + mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_AIL_3); + if (cpu_has_feature(CPU_FTR_ARCH_300) && (current->thread.fscr & FSCR_SCV)) + mtspr(SPRN_FSCR, mfspr(SPRN_FSCR) | FSCR_SCV); + } #endif if (kvmppc_is_split_real(vcpu)) @@ -174,11 +185,6 @@ static void kvmppc_core_vcpu_put_pr(struct kvm_vcpu *vcpu) kvmppc_giveup_fac(vcpu, FSCR_TAR_LG); kvmppc_save_tm_pr(vcpu); - /* Enable AIL if supported */ - if (cpu_has_feature(CPU_FTR_HVMODE) && - cpu_has_feature(CPU_FTR_ARCH_207S)) - mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_AIL_3); - vcpu->cpu = -1; } @@ -1037,6 +1043,8 @@ static int kvmppc_handle_fac(struct kvm_vcpu *vcpu, ulong fac) void kvmppc_set_fscr(struct kvm_vcpu *vcpu, u64 fscr) { + if (fscr & FSCR_SCV) + fscr &= ~FSCR_SCV; /* SCV must not be enabled */ if ((vcpu->arch.fscr & FSCR_TAR) && !(fscr & FSCR_TAR)) { /* TAR got dropped, drop it in shadow too */ kvmppc_giveup_fac(vcpu, FSCR_TAR_LG); From patchwork Tue Feb 22 06:47:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 12754589 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 024A9C433FE for ; Tue, 22 Feb 2022 06:47:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230062AbiBVGsI (ORCPT ); Tue, 22 Feb 2022 01:48:08 -0500 Received: from gmail-smtp-in.l.google.com ([23.128.96.19]:35346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229847AbiBVGsH (ORCPT ); Tue, 22 Feb 2022 01:48:07 -0500 Received: from mail-pf1-x436.google.com (mail-pf1-x436.google.com [IPv6:2607:f8b0:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEC9D10DA41 for ; Mon, 21 Feb 2022 22:47:42 -0800 (PST) Received: by mail-pf1-x436.google.com with SMTP id i21so10997001pfd.13 for ; Mon, 21 Feb 2022 22:47:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=3Yszb1VhW5vQuqMzk14SvDtmn04SSl+6GxkgNXsOtcc=; b=nTfxQGLi3zvpnCIzarK1KAHcr9OUbs6g4uz1ass4kLBNrNGLi6/vww8xDMkk7DhTWB YBMB5DKiT2n8CnwPJeqai5zUQTyH3WVIVVAUQ7BLSEMcf34G+Ek9LALCV5/ns+sFxIJ+ 8ZCGg+Zjd1OnwFBXJchPDB8GfjKVbzHHIf84DA3t9gX2BzzhugTuEiAAQir92Q+Pd0L3 uhizVe0se+EP5skquxJb2+mdOIi66/uBZQNhYS/QNxFNz48MPZDCrw72cRZr5O0t3Dkn 157ap6F4aEh2U6MVT3eCgyM3dxRUYLpI12S+dRKOwpwJzScJPEV4WZSQZux3zT73djji Pr6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=3Yszb1VhW5vQuqMzk14SvDtmn04SSl+6GxkgNXsOtcc=; b=Plb1Tw/pYQx/o/jU1cYFNh6MuvdDOivzV8jHwQdtFNbZuYbD/8kAsSbhkwot4jHzJJ vJdFagaAQ9xUG5gyoFwHcYLrhHNAasI4gRETRKBDKpHRiPBUS+wtlGaxvN4FgsxlVGe2 ezSXBSHqszfQ4qGuMUoeHGnIdLk3LpZYNCaJX5Gnw3nX81oEmyAC4NOFgW9fWAhJJQWl lxpLkYvAoCMK6bvSUYMFSRKU2hhK5WGWFvZM7kqnojlqcSfVRb5io7JJ9P9FV6PFIswz oe9vMUdL2cRzQK8KT8jnxrqKTuWXOFq260zqv9cBgRAf2uYUZkJBmgwSOPA5mJ2TIweN 1ZuA== X-Gm-Message-State: AOAM5325TYdH465bDfSqjpHIP6YPs/5p3mMn0ZdsJR5Ge5TeltDW1GXC uNKiKuW1a1Q+4/W/OAw4rAM= X-Google-Smtp-Source: ABdhPJyKnQMMQNrOXDylnjffub+WBwYSjI2bbl4OUZPem1TdOXRxmNhHZnfjesuPU0PiWaDiIQnIXg== X-Received: by 2002:a05:6a00:14ca:b0:4cf:1930:9d67 with SMTP id w10-20020a056a0014ca00b004cf19309d67mr23076612pfu.55.1645512462337; Mon, 21 Feb 2022 22:47:42 -0800 (PST) Received: from bobo.ibm.com (193-116-225-41.tpgi.com.au. [193.116.225.41]) by smtp.gmail.com with ESMTPSA id d8sm16346711pfv.84.2022.02.21.22.47.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Feb 2022 22:47:42 -0800 (PST) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin , Paolo Bonzini , kvm@vger.kernel.org, Fabiano Rosas Subject: [PATCH v4 2/3] KVM: PPC: Book3S PR: Disallow AIL != 0 Date: Tue, 22 Feb 2022 16:47:26 +1000 Message-Id: <20220222064727.2314380-3-npiggin@gmail.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220222064727.2314380-1-npiggin@gmail.com> References: <20220222064727.2314380-1-npiggin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org KVM PR does not implement address translation modes on interrupt, so it must not allow H_SET_MODE to succeed. The behaviour change caused by this mode is architected and not advisory (interrupts *must* behave differently). QEMU does not deal with differences in AIL support in the host. The solution to that is a spapr capability and corresponding KVM CAP, but this patch does not break things more than before (the host behaviour already differs, this change just disallows some modes that are not implemented properly). By happy coincidence, this allows PR Linux guests that are using the SCV facility to boot and run, because Linux disables the use of SCV if AIL can not be set to 3. This does not fix the underlying problem of missing SCV support (an OS could implement real-mode SCV vectors and try to enable the facility). The true fix for that is for KVM PR to emulate scv interrupts from the facility unavailable interrupt. Reviewed-by: Fabiano Rosas Signed-off-by: Nicholas Piggin --- arch/powerpc/kvm/book3s_pr_papr.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/powerpc/kvm/book3s_pr_papr.c b/arch/powerpc/kvm/book3s_pr_papr.c index 1f10e7dfcdd0..dc4f51ac84bc 100644 --- a/arch/powerpc/kvm/book3s_pr_papr.c +++ b/arch/powerpc/kvm/book3s_pr_papr.c @@ -281,6 +281,22 @@ static int kvmppc_h_pr_logical_ci_store(struct kvm_vcpu *vcpu) return EMULATE_DONE; } +static int kvmppc_h_pr_set_mode(struct kvm_vcpu *vcpu) +{ + unsigned long mflags = kvmppc_get_gpr(vcpu, 4); + unsigned long resource = kvmppc_get_gpr(vcpu, 5); + + if (resource == H_SET_MODE_RESOURCE_ADDR_TRANS_MODE) { + /* KVM PR does not provide AIL!=0 to guests */ + if (mflags == 0) + kvmppc_set_gpr(vcpu, 3, H_SUCCESS); + else + kvmppc_set_gpr(vcpu, 3, H_UNSUPPORTED_FLAG_START - 63); + return EMULATE_DONE; + } + return EMULATE_FAIL; +} + #ifdef CONFIG_SPAPR_TCE_IOMMU static int kvmppc_h_pr_put_tce(struct kvm_vcpu *vcpu) { @@ -384,6 +400,8 @@ int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd) return kvmppc_h_pr_logical_ci_load(vcpu); case H_LOGICAL_CI_STORE: return kvmppc_h_pr_logical_ci_store(vcpu); + case H_SET_MODE: + return kvmppc_h_pr_set_mode(vcpu); case H_XIRR: case H_CPPR: case H_EOI: @@ -421,6 +439,7 @@ int kvmppc_hcall_impl_pr(unsigned long cmd) case H_CEDE: case H_LOGICAL_CI_LOAD: case H_LOGICAL_CI_STORE: + case H_SET_MODE: #ifdef CONFIG_KVM_XICS case H_XIRR: case H_CPPR: @@ -447,6 +466,7 @@ static unsigned int default_hcall_list[] = { H_BULK_REMOVE, H_PUT_TCE, H_CEDE, + H_SET_MODE, #ifdef CONFIG_KVM_XICS H_XIRR, H_CPPR, From patchwork Tue Feb 22 06:47:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 12754590 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83A88C433EF for ; Tue, 22 Feb 2022 06:47:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230214AbiBVGsK (ORCPT ); Tue, 22 Feb 2022 01:48:10 -0500 Received: from gmail-smtp-in.l.google.com ([23.128.96.19]:35432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229847AbiBVGsK (ORCPT ); Tue, 22 Feb 2022 01:48:10 -0500 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5B6310DA41 for ; Mon, 21 Feb 2022 22:47:45 -0800 (PST) Received: by mail-pl1-x631.google.com with SMTP id l8so14784411pls.7 for ; Mon, 21 Feb 2022 22:47:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=zyP1CDnBZz+or+GUa/iSW1eRXWHN1F8ZgUdecrqgvGI=; b=SWk/strLjmDoEYAWt8Ial+BNg08vwBhkBUAUTiIrOm0h9JzI9089awMslPw9rrQLM7 lr7eqFEnycVzvez1IMdL38nWgBzcV/Muzj7l9r2/Y/wnO4J0AK6f/gdoaMhS2FpggY0L HNQGzdbKs0vr0wKftafgEUGw4oA9MQLroskGgNNSFXht6N/jr79GE/r6sT1/D5ikaEwj cl5EKakhOpx+Xs+8iQXiOzjWazMY1zUol1+d8KkdovxV+sl7CJET1TjvOgSRxPGe74bl P8Dzcpr9ScGa3N16cBFtl902HqQUAJTrPCgUImxPQTd8EXV1+az5rNzsTToy58GgH0jF rmZw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=zyP1CDnBZz+or+GUa/iSW1eRXWHN1F8ZgUdecrqgvGI=; b=ifulj7NQdEKJP6PyXHZHfEUypOxuT3NkVpAsit/TyAIBpNaG+4qGCOioMVCrCpPDVw IBbKWixykOIb/1XTyEs6WjjSS99qgn5SMbllIjKtZOtLo71Xk7q35yHpPx2DaYI0o+0w StQuYfxqxyPtCKK60pWHonyMt7NsOOEnsf2NgiiwC/nqvfYaWWuESesuCTPqmTQZnAkJ XKOcKQSBEDA80jkQXR3jC2pcaHnC/sczmkueoriukKAvPIPRqUCNX5JMjvz4GKbyGASF mvr8T5jje+9d8iz1hRQlnvPx/X7Q6GP+Am/C45f1K2e+IpzmuIGqBWbjnS37vXFx7e1E 4HHw== X-Gm-Message-State: AOAM530jXF8S+YQFq/3+zvMxCXgnLOXIhMGrNxIapBD2tNXITH2HlteY ufITcoYBm2Oi3Fbvb65Pwn4= X-Google-Smtp-Source: ABdhPJzOfiyirnWhuN3Uc4DQ4wrL7Ir3DNaGBfpOD/pWn21PotYcLFLrspNR2ceR5MpdIJgZliatsA== X-Received: by 2002:a17:90a:9288:b0:1bc:568b:55bc with SMTP id n8-20020a17090a928800b001bc568b55bcmr2678772pjo.9.1645512465185; Mon, 21 Feb 2022 22:47:45 -0800 (PST) Received: from bobo.ibm.com (193-116-225-41.tpgi.com.au. [193.116.225.41]) by smtp.gmail.com with ESMTPSA id d8sm16346711pfv.84.2022.02.21.22.47.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Feb 2022 22:47:44 -0800 (PST) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin , Paolo Bonzini , kvm@vger.kernel.org, Fabiano Rosas Subject: [PATCH v4 3/3] KVM: PPC: Add KVM_CAP_PPC_AIL_MODE_3 Date: Tue, 22 Feb 2022 16:47:27 +1000 Message-Id: <20220222064727.2314380-4-npiggin@gmail.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220222064727.2314380-1-npiggin@gmail.com> References: <20220222064727.2314380-1-npiggin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Add KVM_CAP_PPC_AIL_MODE_3 to advertise the capability to set the AIL resource mode to 3 with the H_SET_MODE hypercall. This capability differs between processor types and KVM types (PR, HV, Nested HV), and affects guest-visible behaviour. QEMU will implement a cap-ail-mode-3 to control this behaviour[1], and use the KVM CAP if available to determine KVM support[2]. [1] https://lists.nongnu.org/archive/html/qemu-ppc/2022-02/msg00437.html [2] https://lists.nongnu.org/archive/html/qemu-ppc/2022-02/msg00439.html Reviewed-by: Fabiano Rosas Signed-off-by: Nicholas Piggin --- Documentation/virt/kvm/api.rst | 14 ++++++++++++++ arch/powerpc/include/asm/setup.h | 2 ++ arch/powerpc/kvm/powerpc.c | 17 +++++++++++++++++ arch/powerpc/platforms/pseries/setup.c | 12 +++++++++++- include/uapi/linux/kvm.h | 1 + tools/include/uapi/linux/kvm.h | 1 + 6 files changed, 46 insertions(+), 1 deletion(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index a4267104db50..9954568c7eab 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6997,6 +6997,20 @@ indicated by the fd to the VM this is called on. This is intended to support intra-host migration of VMs between userspace VMMs, upgrading the VMM process without interrupting the guest. +7.30 KVM_CAP_PPC_AIL_MODE_3 +------------------------------- + +:Capability: KVM_CAP_PPC_AIL_MODE_3 +:Architectures: ppc +:Type: vm + +This capability indicates that the kernel supports the mode 3 setting for the +"Address Translation Mode on Interrupt" aka "Alternate Interrupt Location" +resource that is controlled with the H_SET_MODE hypercall. + +This capability allows a guest kernel to use a better-performance mode for +handling interrupts and system calls. + 8. Other capabilities. ====================== diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h index d0d3dd531c7f..a555fb77258a 100644 --- a/arch/powerpc/include/asm/setup.h +++ b/arch/powerpc/include/asm/setup.h @@ -28,11 +28,13 @@ void setup_panic(void); #define ARCH_PANIC_TIMEOUT 180 #ifdef CONFIG_PPC_PSERIES +extern bool pseries_reloc_on_exception(void); extern bool pseries_enable_reloc_on_exc(void); extern void pseries_disable_reloc_on_exc(void); extern void pseries_big_endian_exceptions(void); void __init pseries_little_endian_exceptions(void); #else +static inline bool pseries_reloc_on_exception(void) { return false; } static inline bool pseries_enable_reloc_on_exc(void) { return false; } static inline void pseries_disable_reloc_on_exc(void) {} static inline void pseries_big_endian_exceptions(void) {} diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 2ad0ccd202d5..56a6b66d16fe 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -678,6 +678,23 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = 1; break; #endif + case KVM_CAP_PPC_AIL_MODE_3: + r = 0; + /* + * KVM PR, POWER7, and some POWER9s don't support AIL=3 mode. + * The POWER9s can support it if the guest runs in hash mode, + * but QEMU doesn't necessarily query the capability in time. + */ + if (hv_enabled) { + if (kvmhv_on_pseries()) { + if (pseries_reloc_on_exception()) + r = 1; + } else if (cpu_has_feature(CPU_FTR_ARCH_207S) && + !cpu_has_feature(CPU_FTR_P9_RADIX_PREFETCH_BUG)) { + r = 1; + } + } + break; default: r = 0; break; diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 83a04d967a59..182525c2abd5 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -353,6 +353,13 @@ static void pseries_lpar_idle(void) pseries_idle_epilog(); } +static bool pseries_reloc_on_exception_enabled; + +bool pseries_reloc_on_exception(void) +{ + return pseries_reloc_on_exception_enabled; +} + /* * Enable relocation on during exceptions. This has partition wide scope and * may take a while to complete, if it takes longer than one second we will @@ -377,6 +384,7 @@ bool pseries_enable_reloc_on_exc(void) " on exceptions: %ld\n", rc); return false; } + pseries_reloc_on_exception_enabled = true; return true; } @@ -404,7 +412,9 @@ void pseries_disable_reloc_on_exc(void) break; mdelay(get_longbusy_msecs(rc)); } - if (rc != H_SUCCESS) + if (rc == H_SUCCESS) + pseries_reloc_on_exception_enabled = false; + else pr_warn("Warning: Failed to disable relocation on exceptions: %ld\n", rc); } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 5191b57e1562..507ee1f2aa96 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1134,6 +1134,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_VM_GPA_BITS 207 #define KVM_CAP_XSAVE2 208 #define KVM_CAP_SYS_ATTRIBUTES 209 +#define KVM_CAP_PPC_AIL_MODE_3 210 #ifdef KVM_CAP_IRQ_ROUTING diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h index 5191b57e1562..507ee1f2aa96 100644 --- a/tools/include/uapi/linux/kvm.h +++ b/tools/include/uapi/linux/kvm.h @@ -1134,6 +1134,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_VM_GPA_BITS 207 #define KVM_CAP_XSAVE2 208 #define KVM_CAP_SYS_ATTRIBUTES 209 +#define KVM_CAP_PPC_AIL_MODE_3 210 #ifdef KVM_CAP_IRQ_ROUTING