From patchwork Sun Jun 9 15:49:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Saenz Julienne X-Patchwork-Id: 13691260 Received: from smtp-fw-6001.amazon.com (smtp-fw-6001.amazon.com [52.95.48.154]) (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 F1E28446DE; Sun, 9 Jun 2024 15:51:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.95.48.154 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717948267; cv=none; b=HNXfLrAf5TUM3mCWrZPjHxI3C6x0tBMv9UBeEAQaE3tE4Orsa1s7GXTGjxU4vzn44YB4fCA2Nu2g9PgLH3ayValV4GjVtS0pWIYsLfqlMce4So1CqXpXgMSanYc5tTSNJGiW/7w+gfi/guhXT6IKNOaLYsw9Kc97I8tC67KKDqc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717948267; c=relaxed/simple; bh=cF25vajOKkfbhKDftt1MB4QKPKKFtwT/VnYRGJnzbM8=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Wkuk+5hX1El5j2Pf9wc9KJzwca2qNBZ+KcrOsJjkCwxDqjCdRDTqctV1gJUruUJuKsqmSbzawyqQGOdi7ZhGTphkEtW6vJozeSFYAf5KvXTAI/7TP4XxQ7s0ju/22grHlKQkbw6NaxKvqBnO9ydAwuAW4WlXnqO9G4VuhQfEYaA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.es; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=mDYNVB6G; arc=none smtp.client-ip=52.95.48.154 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.es Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="mDYNVB6G" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1717948265; x=1749484265; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=0Kf/k8Ifp+IJgoAkFqq7BEZyoJRgq+MCrSwCJITAKBQ=; b=mDYNVB6GMK51cPoj5yLTHWLuHTFBzMY+72w0sG5vpqxVVdBMoj5csnlp j1ECqcrZOX+UW81VVq5WHNKK6Do1Ut6No9h4lcNnRdmgEp92JKELW7lLr s53DlKlD9M27utDGWwuNSaiajiYyq+yBV9wIi7pYQqSvrao8j3uquWGaX g=; X-IronPort-AV: E=Sophos;i="6.08,225,1712620800"; d="scan'208";a="402162296" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.43.8.2]) by smtp-border-fw-6001.iad6.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jun 2024 15:51:01 +0000 Received: from EX19MTAEUC001.ant.amazon.com [10.0.17.79:12461] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.26.236:2525] with esmtp (Farcaster) id d4395843-8a2c-4c0c-857a-37daf136215b; Sun, 9 Jun 2024 15:50:59 +0000 (UTC) X-Farcaster-Flow-ID: d4395843-8a2c-4c0c-857a-37daf136215b Received: from EX19D004EUC001.ant.amazon.com (10.252.51.190) by EX19MTAEUC001.ant.amazon.com (10.252.51.155) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Sun, 9 Jun 2024 15:50:59 +0000 Received: from dev-dsk-nsaenz-1b-189b39ae.eu-west-1.amazon.com (10.13.235.138) by EX19D004EUC001.ant.amazon.com (10.252.51.190) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Sun, 9 Jun 2024 15:50:53 +0000 From: Nicolas Saenz Julienne To: , CC: , , , , , , , , , , , , , , , , , , , , Subject: [PATCH 01/18] KVM: x86: hyper-v: Introduce XMM output support Date: Sun, 9 Jun 2024 15:49:29 +0000 Message-ID: <20240609154945.55332-2-nsaenz@amazon.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240609154945.55332-1-nsaenz@amazon.com> References: <20240609154945.55332-1-nsaenz@amazon.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D041UWA001.ant.amazon.com (10.13.139.124) To EX19D004EUC001.ant.amazon.com (10.252.51.190) Prepare infrastructure to be able to return data through the XMM registers when Hyper-V hypercalls are issues in fast mode. The XMM registers are exposed to user-space through KVM_EXIT_HYPERV_HCALL and restored on successful hypercall completion. Signed-off-by: Nicolas Saenz Julienne --- There was some discussion in the RFC about whether growing 'struct kvm_hyperv_exit' is ABI breakage. IMO it isn't: - There is padding in 'struct kvm_run' that ensures that a bigger 'struct kvm_hyperv_exit' doesn't alter the offsets within that struct. - Adding a new field at the bottom of the 'hcall' field within the 'struct kvm_hyperv_exit' should be fine as well, as it doesn't alter the offsets within that struct either. - Ultimately, previous updates to 'struct kvm_hyperv_exit's hint that its size isn't part of the uABI. It already grew when syndbg was introduced. Documentation/virt/kvm/api.rst | 19 ++++++++++ arch/x86/include/asm/hyperv-tlfs.h | 2 +- arch/x86/kvm/hyperv.c | 56 +++++++++++++++++++++++++++++- include/uapi/linux/kvm.h | 6 ++++ 4 files changed, 81 insertions(+), 2 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index a71d91978d9ef..17893b330b76f 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -8893,3 +8893,22 @@ Ordering of KVM_GET_*/KVM_SET_* ioctls ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ TBD + +10. Hyper-V CPUIDs +================== + +This section only applies to x86. + +New Hyper-V feature support is no longer being tracked through KVM +capabilities. Userspace can check if a particular version of KVM supports a +feature using KMV_GET_SUPPORTED_HV_CPUID. This section documents how Hyper-V +CPUIDs map to KVM functionality. + +10.1 HV_X64_HYPERCALL_XMM_OUTPUT_AVAILABLE +------------------------------------------ + +:Location: CPUID.40000003H:EDX[bit 15] + +This CPUID indicates that KVM supports retuning data to the guest in response +to a hypercall using the XMM registers. It also extends ``struct +kvm_hyperv_exit`` to allow passing the XMM data from userspace. diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index 3787d26810c1c..6a18c9f77d5fe 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h @@ -49,7 +49,7 @@ /* Support for physical CPU dynamic partitioning events is available*/ #define HV_X64_CPU_DYNAMIC_PARTITIONING_AVAILABLE BIT(3) /* - * Support for passing hypercall input parameter block via XMM + * Support for passing hypercall input and output parameter block via XMM * registers is available */ #define HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE BIT(4) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 8a47f8541eab7..42f44546fe79c 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1865,6 +1865,7 @@ struct kvm_hv_hcall { u16 rep_idx; bool fast; bool rep; + bool xmm_dirty; sse128_t xmm[HV_HYPERCALL_MAX_XMM_REGISTERS]; /* @@ -2396,9 +2397,49 @@ static int kvm_hv_hypercall_complete(struct kvm_vcpu *vcpu, u64 result) return ret; } +static void kvm_hv_write_xmm(struct kvm_hyperv_xmm_reg *xmm) +{ + int reg; + + kvm_fpu_get(); + for (reg = 0; reg < HV_HYPERCALL_MAX_XMM_REGISTERS; reg++) { + const sse128_t data = sse128(xmm[reg].low, xmm[reg].high); + _kvm_write_sse_reg(reg, &data); + } + kvm_fpu_put(); +} + +static bool kvm_hv_is_xmm_output_hcall(u16 code) +{ + return false; +} + +static bool kvm_hv_xmm_output_allowed(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); + + return !hv_vcpu->enforce_cpuid || + hv_vcpu->cpuid_cache.features_edx & + HV_X64_HYPERCALL_XMM_OUTPUT_AVAILABLE; +} + static int kvm_hv_hypercall_complete_userspace(struct kvm_vcpu *vcpu) { - return kvm_hv_hypercall_complete(vcpu, vcpu->run->hyperv.u.hcall.result); + bool fast = !!(vcpu->run->hyperv.u.hcall.input & HV_HYPERCALL_FAST_BIT); + u16 code = vcpu->run->hyperv.u.hcall.input & 0xffff; + u64 result = vcpu->run->hyperv.u.hcall.result; + + if (hv_result_success(result) && fast && + kvm_hv_is_xmm_output_hcall(code)) { + if (unlikely(!kvm_hv_xmm_output_allowed(vcpu))) { + kvm_queue_exception(vcpu, UD_VECTOR); + return 1; + } + + kvm_hv_write_xmm(vcpu->run->hyperv.u.hcall.xmm); + } + + return kvm_hv_hypercall_complete(vcpu, result); } static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) @@ -2553,6 +2594,7 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) hc.rep_cnt = (hc.param >> HV_HYPERCALL_REP_COMP_OFFSET) & 0xfff; hc.rep_idx = (hc.param >> HV_HYPERCALL_REP_START_OFFSET) & 0xfff; hc.rep = !!(hc.rep_cnt || hc.rep_idx); + hc.xmm_dirty = false; trace_kvm_hv_hypercall(hc.code, hc.fast, hc.var_cnt, hc.rep_cnt, hc.rep_idx, hc.ingpa, hc.outgpa); @@ -2673,6 +2715,15 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) break; } + if (hv_result_success(ret) && hc.xmm_dirty) { + if (unlikely(!kvm_hv_xmm_output_allowed(vcpu))) { + kvm_queue_exception(vcpu, UD_VECTOR); + return 1; + } + + kvm_hv_write_xmm((struct kvm_hyperv_xmm_reg *)hc.xmm); + } + hypercall_complete: return kvm_hv_hypercall_complete(vcpu, ret); @@ -2682,6 +2733,8 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) vcpu->run->hyperv.u.hcall.input = hc.param; vcpu->run->hyperv.u.hcall.params[0] = hc.ingpa; vcpu->run->hyperv.u.hcall.params[1] = hc.outgpa; + if (hc.fast) + memcpy(vcpu->run->hyperv.u.hcall.xmm, hc.xmm, sizeof(hc.xmm)); vcpu->arch.complete_userspace_io = kvm_hv_hypercall_complete_userspace; return 0; } @@ -2830,6 +2883,7 @@ int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, ent->ebx |= HV_ENABLE_EXTENDED_HYPERCALLS; ent->edx |= HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE; + ent->edx |= HV_X64_HYPERCALL_XMM_OUTPUT_AVAILABLE; ent->edx |= HV_FEATURE_FREQUENCY_MSRS_AVAILABLE; ent->edx |= HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index d03842abae578..fbdee8d754595 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -90,6 +90,11 @@ struct kvm_pit_config { #define KVM_PIT_SPEAKER_DUMMY 1 +struct kvm_hyperv_xmm_reg { + __u64 low; + __u64 high; +}; + struct kvm_hyperv_exit { #define KVM_EXIT_HYPERV_SYNIC 1 #define KVM_EXIT_HYPERV_HCALL 2 @@ -108,6 +113,7 @@ struct kvm_hyperv_exit { __u64 input; __u64 result; __u64 params[2]; + struct kvm_hyperv_xmm_reg xmm[6]; } hcall; struct { __u32 msr;