From nobody Sat Oct 4 03:01:36 2025 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A375A2ECD26 for ; Thu, 21 Aug 2025 04:29:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755750593; cv=none; b=XeYko4N060Tyn9fT/KX3LLtknyDAR2OkKNup6zhu9h9KOGUdkC895CztfwiZodzlzamd3MUkw02pa+yXSJFQvPYWMZdaVAIHwNuY393h7/yV0EaXSsI4yHvFqgUAVVa+o4nktapO0adayWSnRw7YS4zQAkp3bnXwLyl4vrwz3NY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755750593; c=relaxed/simple; bh=9+eQprqBsQ6gxSE3z+RPqS3r7N8HYybLZbylKvd7iWA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=owNOyrtBLXKdL9282K1I7atsngSzAvCNc9KuOuKL/xTOyreJVgjMe881Xc6iA4WZ65hdQn3JPpomvkvqMZbDl9KzPmtY6w4HrVnxt/tTZcXSeKGideUDRZHi/3Lu5L4OwGS9XCfZRGz93/7xO57D5ZdVGz3/XC8tqq1Y2yYQT/M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--sagis.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=loPsoVTU; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--sagis.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="loPsoVTU" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-32326bf571bso1409592a91.2 for ; Wed, 20 Aug 2025 21:29:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1755750591; x=1756355391; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=C+Vn2dydaOWO4V7Wr4fQ6A3nnlLiDSULKiE6J6INVZA=; b=loPsoVTU0O3ATp7otV70VbPJxJuQk/2j0ZPoKXZ7mXN/l8hLXHisNus9Blll0W/gAg KHLKOseGeE5pktXeHWprdojDfjfdRRwUQNVSfzrvfFwn0SCC8MoY2bPDC6G9y/wrMVQu aocGGX8Up9RJGxaXGuuQoVzpE7rLvLUTxMY44QT4Gbmj70I6uhYvknsBVR6hybkzq6OR 6Av+rmdPtPtENUv2HaMa1EA5brrq4ESDMxNaHxgJCAWoExiZlLQycnLuv/VSYwBlLmLU +4YBRiheOJ+sQ/aFAoPwyAmTqvrWl3vkLp+8fGTRkc7qVsVQia8wSHL5/WfSzZt2xPFy nBeA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755750591; x=1756355391; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=C+Vn2dydaOWO4V7Wr4fQ6A3nnlLiDSULKiE6J6INVZA=; b=E5wuedxob679MM9tusPX803BusIyZ7sTLImxRbueA6qLoO4qfP4R9QTU0XFC1JpEpi 0AA2RZik5vZWnS0SVH4IfOyKi1gmOjNGp5lbW0oVJp9d11lP3XfhD2DNnNk0BlElKTCA aGJZggYox8AeLmC1eAhMCvm7tZZ1wtCycVjEzBKsm9XFXIZcLsvGfZhS9UHL+NfoE56W xXI8JpRFqYThwuhxAUFFziZJhl4BqlJxMC4vy0cE5LUxY3rHixnRKCJiGXWKHAmAz7K0 HNMYuYZrldmnkurcudx42D/r/coiImOWG12h6m8xAubqbCMahxAnMgoyRY3qUOIy7Ohu ZC2A== X-Gm-Message-State: AOJu0Ywe+gxS+c7ZQMXt2iT8vbIaLvcl7+7mAnHZTD/dursk7JjBWL5z 4+OoAsE1qbZYU8bCLiUhaP+MgoPQ79GEzFjrRXvZg/4GUz/ZxCEeo9jlMNu6/MUlbOgMXG0c5fR 9Ug== X-Google-Smtp-Source: AGHT+IHnoZkxggDv6fXD1tHDt5+rOVqRbveDiJ7W0a/Y7B0nOodBtUYvH6G1D7HFbnYFBe8qgKggtU4fUA== X-Received: from pjbnb18.prod.google.com ([2002:a17:90b:35d2:b0:321:c36d:1b8a]) (user=sagis job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:2e0e:b0:31e:d929:5ca5 with SMTP id 98e67ed59e1d1-324ed06131bmr1483288a91.1.1755750591038; Wed, 20 Aug 2025 21:29:51 -0700 (PDT) Date: Wed, 20 Aug 2025 21:29:11 -0700 In-Reply-To: <20250821042915.3712925-1-sagis@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250821042915.3712925-1-sagis@google.com> X-Mailer: git-send-email 2.51.0.rc1.193.gad69d77794-goog Message-ID: <20250821042915.3712925-19-sagis@google.com> Subject: [PATCH v9 18/19] KVM: selftests: Add ucall support for TDX From: Sagi Shahar To: linux-kselftest@vger.kernel.org, Paolo Bonzini , Shuah Khan , Sean Christopherson , Ackerley Tng , Ryan Afranji , Andrew Jones , Isaku Yamahata , Erdem Aktas , Rick Edgecombe , Sagi Shahar , Roger Wang , Binbin Wu , Oliver Upton , "Pratik R. Sampat" , Reinette Chatre , Ira Weiny , Chao Gao , Chenyi Qiang Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Ackerley Tng ucalls for non-Coco VMs work by having the guest write to the rdi register, then perform an io instruction to exit to the host. The host then reads rdi using kvm_get_regs(). CPU registers can't be read using kvm_get_regs() for TDX, so TDX guests use MMIO to pass the struct ucall's hva to the host. MMIO was chosen because it is one of the simplest (hence unlikely to fail) mechanisms that support passing 8 bytes from guest to host. Signed-off-by: Ackerley Tng Co-developed-by: Sagi Shahar Signed-off-by: Sagi Shahar --- .../testing/selftests/kvm/include/x86/ucall.h | 4 +- tools/testing/selftests/kvm/lib/x86/ucall.c | 45 ++++++++++++++++--- 2 files changed, 41 insertions(+), 8 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86/ucall.h b/tools/testin= g/selftests/kvm/include/x86/ucall.h index d3825dcc3cd9..0494a4a21557 100644 --- a/tools/testing/selftests/kvm/include/x86/ucall.h +++ b/tools/testing/selftests/kvm/include/x86/ucall.h @@ -6,8 +6,6 @@ =20 #define UCALL_EXIT_REASON KVM_EXIT_IO =20 -static inline void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa) -{ -} +void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa); =20 #endif diff --git a/tools/testing/selftests/kvm/lib/x86/ucall.c b/tools/testing/se= lftests/kvm/lib/x86/ucall.c index 1265cecc7dd1..0ad24baaa3c4 100644 --- a/tools/testing/selftests/kvm/lib/x86/ucall.c +++ b/tools/testing/selftests/kvm/lib/x86/ucall.c @@ -5,11 +5,34 @@ * Copyright (C) 2018, Red Hat, Inc. */ #include "kvm_util.h" +#include "tdx/tdx.h" =20 #define UCALL_PIO_PORT ((uint16_t)0x1000) =20 +static uint8_t vm_type; +static vm_paddr_t host_ucall_mmio_gpa; +static vm_paddr_t ucall_mmio_gpa; + +void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa) +{ + vm_type =3D vm->type; + sync_global_to_guest(vm, vm_type); + + host_ucall_mmio_gpa =3D ucall_mmio_gpa =3D mmio_gpa; + + if (vm_type =3D=3D KVM_X86_TDX_VM) + ucall_mmio_gpa |=3D vm->arch.s_bit; + + sync_global_to_guest(vm, ucall_mmio_gpa); +} + void ucall_arch_do_ucall(vm_vaddr_t uc) { + if (vm_type =3D=3D KVM_X86_TDX_VM) { + tdg_vp_vmcall_ve_request_mmio_write(ucall_mmio_gpa, 8, uc); + return; + } + /* * FIXME: Revert this hack (the entire commit that added it) once nVMX * preserves L2 GPRs across a nested VM-Exit. If a ucall from L2, e.g. @@ -46,11 +69,23 @@ void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu) { struct kvm_run *run =3D vcpu->run; =20 - if (run->exit_reason =3D=3D KVM_EXIT_IO && run->io.port =3D=3D UCALL_PIO_= PORT) { - struct kvm_regs regs; + switch (vm_type) { + case KVM_X86_TDX_VM: + if (vcpu->run->exit_reason =3D=3D KVM_EXIT_MMIO && + vcpu->run->mmio.phys_addr =3D=3D host_ucall_mmio_gpa && + vcpu->run->mmio.len =3D=3D 8 && vcpu->run->mmio.is_write) { + uint64_t data =3D *(uint64_t *)vcpu->run->mmio.data; + + return (void *)data; + } + return NULL; + default: + if (run->exit_reason =3D=3D KVM_EXIT_IO && run->io.port =3D=3D UCALL_PIO= _PORT) { + struct kvm_regs regs; =20 - vcpu_regs_get(vcpu, ®s); - return (void *)regs.rdi; + vcpu_regs_get(vcpu, ®s); + return (void *)regs.rdi; + } + return NULL; } - return NULL; } --=20 2.51.0.rc1.193.gad69d77794-goog