From: Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Kai Huang <kai.huang@intel.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: linux-mm@kvack.org, seanjc@google.com, pbonzini@redhat.com,
dave.hansen@intel.com, dan.j.williams@intel.com,
rafael.j.wysocki@intel.com, kirill.shutemov@linux.intel.com,
ying.huang@intel.com, reinette.chatre@intel.com,
len.brown@intel.com, tony.luck@intel.com, peterz@infradead.org,
ak@linux.intel.com, isaku.yamahata@intel.com, chao.gao@intel.com,
bagasdotme@gmail.com, sagis@google.com, imammedo@redhat.com
Subject: Re: [PATCH v7 02/20] x86/virt/tdx: Detect TDX during kernel boot
Date: Sun, 20 Nov 2022 19:07:28 -0800 [thread overview]
Message-ID: <3e4644e4-d939-7f15-02e1-a6be1ed7f932@linux.intel.com> (raw)
In-Reply-To: <aaee2d5332a97c840ad401ba935842a998a877ec.1668988357.git.kai.huang@intel.com>
On 11/20/22 4:26 PM, Kai Huang wrote:
> Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
> host and certain physical attacks. A CPU-attested software module
> called 'the TDX module' runs inside a new isolated memory range as a
> trusted hypervisor to manage and run protected VMs.
>
> Pre-TDX Intel hardware has support for a memory encryption architecture
> called MKTME. The memory encryption hardware underpinning MKTME is also
> used for Intel TDX. TDX ends up "stealing" some of the physical address
> space from the MKTME architecture for crypto-protection to VMs. The
> BIOS is responsible for partitioning the "KeyID" space between legacy
> MKTME and TDX. The KeyIDs reserved for TDX are called 'TDX private
> KeyIDs' or 'TDX KeyIDs' for short.
>
> TDX doesn't trust the BIOS. During machine boot, TDX verifies the TDX
> private KeyIDs are consistently and correctly programmed by the BIOS
> across all CPU packages before it enables TDX on any CPU core. A valid
> TDX private KeyID range on BSP indicates TDX has been enabled by the
> BIOS, otherwise the BIOS is buggy.
>
> The TDX module is expected to be loaded by the BIOS when it enables TDX,
> but the kernel needs to properly initialize it before it can be used to
> create and run any TDX guests. The TDX module will be initialized at
> runtime by the user (i.e. KVM) on demand.
>
> Add a new early_initcall(tdx_init) to do TDX early boot initialization.
> Only detect TDX private KeyIDs for now. Some other early checks will
> follow up. Also add a new function to report whether TDX has been
> enabled by BIOS (TDX private KeyID range is valid). Kexec() will also
> need it to determine whether need to flush dirty cachelines that are
> associated with any TDX private KeyIDs before booting to the new kernel.
>
> To start to support TDX, create a new arch/x86/virt/vmx/tdx/tdx.c for
> TDX host kernel support. Add a new Kconfig option CONFIG_INTEL_TDX_HOST
> to opt-in TDX host kernel support (to distinguish with TDX guest kernel
> support). So far only KVM is the only user of TDX. Make the new config
> option depend on KVM_INTEL.
>
> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Signed-off-by: Kai Huang <kai.huang@intel.com>
> ---
>
> v6 -> v7:
> - No change.
>
> v5 -> v6:
> - Removed SEAMRR detection to make code simpler.
> - Removed the 'default N' in the KVM_TDX_HOST Kconfig (Kirill).
> - Changed to use 'obj-y' in arch/x86/virt/vmx/tdx/Makefile (Kirill).
>
>
> ---
> arch/x86/Kconfig | 12 +++++
> arch/x86/Makefile | 2 +
> arch/x86/include/asm/tdx.h | 7 +++
> arch/x86/virt/Makefile | 2 +
> arch/x86/virt/vmx/Makefile | 2 +
> arch/x86/virt/vmx/tdx/Makefile | 2 +
> arch/x86/virt/vmx/tdx/tdx.c | 95 ++++++++++++++++++++++++++++++++++
> arch/x86/virt/vmx/tdx/tdx.h | 15 ++++++
> 8 files changed, 137 insertions(+)
> create mode 100644 arch/x86/virt/Makefile
> create mode 100644 arch/x86/virt/vmx/Makefile
> create mode 100644 arch/x86/virt/vmx/tdx/Makefile
> create mode 100644 arch/x86/virt/vmx/tdx/tdx.c
> create mode 100644 arch/x86/virt/vmx/tdx/tdx.h
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 67745ceab0db..cced4ef3bfb2 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1953,6 +1953,18 @@ config X86_SGX
>
> If unsure, say N.
>
> +config INTEL_TDX_HOST
> + bool "Intel Trust Domain Extensions (TDX) host support"
> + depends on CPU_SUP_INTEL
> + depends on X86_64
> + depends on KVM_INTEL
> + help
> + Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
> + host and certain physical attacks. This option enables necessary TDX
> + support in host kernel to run protected VMs.
> +
> + If unsure, say N.
> +
> config EFI
> bool "EFI runtime service support"
> depends on ACPI
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 415a5d138de4..38d3e8addc5f 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -246,6 +246,8 @@ archheaders:
>
> libs-y += arch/x86/lib/
>
> +core-y += arch/x86/virt/
> +
> # drivers-y are linked after core-y
> drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
> drivers-$(CONFIG_PCI) += arch/x86/pci/
> diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
> index e9a3f4a6fba1..51c4222a13ae 100644
> --- a/arch/x86/include/asm/tdx.h
> +++ b/arch/x86/include/asm/tdx.h
> @@ -98,5 +98,12 @@ static inline long tdx_kvm_hypercall(unsigned int nr, unsigned long p1,
> return -ENODEV;
> }
> #endif /* CONFIG_INTEL_TDX_GUEST && CONFIG_KVM_GUEST */
> +
> +#ifdef CONFIG_INTEL_TDX_HOST
> +bool platform_tdx_enabled(void);
> +#else /* !CONFIG_INTEL_TDX_HOST */
> +static inline bool platform_tdx_enabled(void) { return false; }
> +#endif /* CONFIG_INTEL_TDX_HOST */
> +
> #endif /* !__ASSEMBLY__ */
> #endif /* _ASM_X86_TDX_H */
> diff --git a/arch/x86/virt/Makefile b/arch/x86/virt/Makefile
> new file mode 100644
> index 000000000000..1e36502cd738
> --- /dev/null
> +++ b/arch/x86/virt/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-y += vmx/
> diff --git a/arch/x86/virt/vmx/Makefile b/arch/x86/virt/vmx/Makefile
> new file mode 100644
> index 000000000000..feebda21d793
> --- /dev/null
> +++ b/arch/x86/virt/vmx/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-$(CONFIG_INTEL_TDX_HOST) += tdx/
> diff --git a/arch/x86/virt/vmx/tdx/Makefile b/arch/x86/virt/vmx/tdx/Makefile
> new file mode 100644
> index 000000000000..93ca8b73e1f1
> --- /dev/null
> +++ b/arch/x86/virt/vmx/tdx/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-y += tdx.o
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> new file mode 100644
> index 000000000000..982d9c453b6b
> --- /dev/null
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -0,0 +1,95 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright(c) 2022 Intel Corporation.
> + *
> + * Intel Trusted Domain Extensions (TDX) support
> + */
> +
> +#define pr_fmt(fmt) "tdx: " fmt
> +
> +#include <linux/types.h>
> +#include <linux/init.h>
> +#include <linux/printk.h>
> +#include <asm/msr-index.h>
> +#include <asm/msr.h>
> +#include <asm/tdx.h>
> +#include "tdx.h"
> +
> +static u32 tdx_keyid_start __ro_after_init;
> +static u32 tdx_keyid_num __ro_after_init;
> +
> +/*
> + * Detect TDX private KeyIDs to see whether TDX has been enabled by the
> + * BIOS. Both initializing the TDX module and running TDX guest require
> + * TDX private KeyID.
> + *
> + * TDX doesn't trust BIOS. TDX verifies all configurations from BIOS
> + * are correct before enabling TDX on any core. TDX requires the BIOS
> + * to correctly and consistently program TDX private KeyIDs on all CPU
> + * packages. Unless there is a BIOS bug, detecting a valid TDX private
> + * KeyID range on BSP indicates TDX has been enabled by the BIOS. If
> + * there's such BIOS bug, it will be caught later when initializing the
> + * TDX module.
> + */
> +static int __init detect_tdx(void)
> +{
> + int ret;
> +
> + /*
> + * IA32_MKTME_KEYID_PARTIONING:
> + * Bit [31:0]: Number of MKTME KeyIDs.
> + * Bit [63:32]: Number of TDX private KeyIDs.
> + */
> + ret = rdmsr_safe(MSR_IA32_MKTME_KEYID_PARTITIONING, &tdx_keyid_start,
> + &tdx_keyid_num);
> + if (ret)
> + return -ENODEV;
> +
> + if (!tdx_keyid_num)
> + return -ENODEV;
> +
> + /*
> + * KeyID 0 is for TME. MKTME KeyIDs start from 1. TDX private
> + * KeyIDs start after the last MKTME KeyID.
> + */
> + tdx_keyid_start++;
It is not very clear why you increment tdx_keyid_start. What we read from
MSR_IA32_MKTME_KEYID_PARTITIONING is not the correct start keyid?
Also why is this global variable? At least in this patch, there seems to
be no use case.
> +
> + pr_info("TDX enabled by BIOS. TDX private KeyID range: [%u, %u)\n",
> + tdx_keyid_start, tdx_keyid_start + tdx_keyid_num);
> +
> + return 0;
> +}
> +
> +static void __init clear_tdx(void)
> +{
> + tdx_keyid_start = tdx_keyid_num = 0;
> +}
> +
> +static int __init tdx_init(void)
> +{
> + if (detect_tdx())
> + return -ENODEV;
> +
> + /*
> + * Initializing the TDX module requires one TDX private KeyID.
> + * If there's only one TDX KeyID then after module initialization
> + * KVM won't be able to run any TDX guest, which makes the whole
> + * thing worthless. Just disable TDX in this case.
> + */
> + if (tdx_keyid_num < 2) {
> + pr_info("Disable TDX as there's only one TDX private KeyID available.\n");
> + goto no_tdx;
> + }
> +
> + return 0;
> +no_tdx:
> + clear_tdx();
> + return -ENODEV;
> +}
> +early_initcall(tdx_init);
> +
> +/* Return whether the BIOS has enabled TDX */
> +bool platform_tdx_enabled(void)
> +{
> + return !!tdx_keyid_num;
> +}
> diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
> new file mode 100644
> index 000000000000..d00074abcb20
> --- /dev/null
> +++ b/arch/x86/virt/vmx/tdx/tdx.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _X86_VIRT_TDX_H
> +#define _X86_VIRT_TDX_H
> +
> +/*
> + * This file contains both macros and data structures defined by the TDX
> + * architecture and Linux defined software data structures and functions.
> + * The two should not be mixed together for better readability. The
> + * architectural definitions come first.
> + */
> +
> +/* MSR to report KeyID partitioning between MKTME and TDX */
> +#define MSR_IA32_MKTME_KEYID_PARTITIONING 0x00000087
> +
> +#endif
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
next prev parent reply other threads:[~2022-11-21 3:07 UTC|newest]
Thread overview: 163+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-21 0:26 [PATCH v7 00/20] TDX host kernel support Kai Huang
2022-11-21 0:26 ` [PATCH v7 01/20] x86/tdx: Define TDX supported page sizes as macros Kai Huang
2022-11-21 2:52 ` Sathyanarayanan Kuppuswamy
2022-11-21 9:15 ` Huang, Kai
2022-11-21 17:23 ` Sathyanarayanan Kuppuswamy
2022-11-21 18:12 ` Dave Hansen
2022-11-21 23:48 ` Dave Hansen
2022-11-22 0:01 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 02/20] x86/virt/tdx: Detect TDX during kernel boot Kai Huang
2022-11-21 3:07 ` Sathyanarayanan Kuppuswamy [this message]
2022-11-21 9:37 ` Huang, Kai
2022-11-21 23:57 ` Sathyanarayanan Kuppuswamy
2022-11-22 0:10 ` Dave Hansen
2022-11-22 11:28 ` Huang, Kai
2022-11-22 16:50 ` Dave Hansen
2022-11-22 23:21 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 03/20] x86/virt/tdx: Disable TDX if X2APIC is not enabled Kai Huang
2022-11-21 3:51 ` Sathyanarayanan Kuppuswamy
2022-11-21 9:44 ` Huang, Kai
2022-11-21 22:00 ` Sathyanarayanan Kuppuswamy
2022-11-21 23:40 ` Huang, Kai
2022-11-21 23:46 ` Dave Hansen
2022-11-22 0:30 ` Huang, Kai
2022-11-22 0:44 ` Dave Hansen
2022-11-22 0:58 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 04/20] x86/virt/tdx: Add skeleton to initialize TDX on demand Kai Huang
2022-11-22 9:02 ` Peter Zijlstra
2022-11-22 10:31 ` Thomas Gleixner
2022-11-22 15:35 ` Dave Hansen
2022-11-22 20:03 ` Thomas Gleixner
2022-11-22 20:11 ` Sean Christopherson
2022-11-23 0:30 ` Huang, Kai
2022-11-23 1:12 ` Huang, Kai
2022-11-23 11:05 ` Thomas Gleixner
2022-11-23 12:22 ` Huang, Kai
2022-11-22 18:05 ` Dave Hansen
2022-11-23 10:18 ` Huang, Kai
2022-11-23 16:58 ` Dave Hansen
2022-11-23 21:58 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 05/20] x86/virt/tdx: Implement functions to make SEAMCALL Kai Huang
2022-11-22 9:06 ` Peter Zijlstra
2022-11-23 8:53 ` Huang, Kai
2022-11-22 18:20 ` Dave Hansen
2022-11-23 10:43 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 06/20] x86/virt/tdx: Shut down TDX module in case of error Kai Huang
2022-11-22 9:10 ` Peter Zijlstra
2022-11-22 9:13 ` Peter Zijlstra
2022-11-22 15:14 ` Dave Hansen
2022-11-22 19:13 ` Peter Zijlstra
2022-11-22 19:24 ` Dave Hansen
2022-11-22 19:33 ` Peter Zijlstra
2022-11-23 1:14 ` Huang, Kai
2022-11-29 21:40 ` Dave Hansen
2022-11-30 11:09 ` Thomas Gleixner
2022-11-23 0:58 ` Huang, Kai
2022-11-23 1:04 ` Dave Hansen
2022-11-23 1:22 ` Huang, Kai
2022-11-23 16:20 ` Sean Christopherson
2022-11-23 16:41 ` Dave Hansen
2022-11-23 17:37 ` Sean Christopherson
2022-11-23 18:18 ` Dave Hansen
2022-11-23 19:03 ` Sean Christopherson
2022-11-22 9:20 ` Peter Zijlstra
2022-11-22 15:06 ` Thomas Gleixner
2022-11-22 19:06 ` Peter Zijlstra
2022-11-22 19:31 ` Sean Christopherson
2022-11-23 9:39 ` Huang, Kai
2022-11-22 15:20 ` Dave Hansen
2022-11-22 16:52 ` Thomas Gleixner
2022-11-22 18:57 ` Dave Hansen
2022-11-22 19:14 ` Peter Zijlstra
2022-11-23 1:24 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 07/20] x86/virt/tdx: Do TDX module global initialization Kai Huang
2022-11-22 19:14 ` Dave Hansen
2022-11-23 11:45 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 08/20] x86/virt/tdx: Do logical-cpu scope TDX module initialization Kai Huang
2022-11-21 0:26 ` [PATCH v7 09/20] x86/virt/tdx: Get information about TDX module and TDX-capable memory Kai Huang
2022-11-22 23:39 ` Dave Hansen
2022-11-23 11:40 ` Huang, Kai
2022-11-23 16:44 ` Dave Hansen
2022-11-23 22:53 ` Huang, Kai
2022-12-02 11:19 ` Huang, Kai
2022-12-02 17:25 ` Dave Hansen
2022-12-02 21:57 ` Huang, Kai
2022-12-02 11:11 ` Huang, Kai
2022-12-02 17:06 ` Dave Hansen
2022-12-02 21:56 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 10/20] x86/virt/tdx: Use all system memory when initializing TDX module as TDX memory Kai Huang
2022-11-21 5:37 ` Huang, Ying
2022-11-21 9:09 ` Huang, Kai
2022-11-22 1:54 ` Huang, Ying
2022-11-22 9:16 ` Huang, Kai
2022-11-24 0:47 ` Huang, Ying
2022-11-22 10:10 ` Peter Zijlstra
2022-11-22 11:40 ` Huang, Kai
2022-11-23 0:21 ` Dave Hansen
2022-11-23 9:29 ` Peter Zijlstra
2022-11-24 1:04 ` Huang, Kai
2022-11-24 1:22 ` Dave Hansen
2022-11-24 2:27 ` Huang, Kai
2022-11-24 1:50 ` Dan Williams
2022-11-24 9:06 ` Huang, Kai
2022-11-25 9:28 ` David Hildenbrand
2022-11-28 8:38 ` Huang, Kai
2022-11-28 8:43 ` David Hildenbrand
2022-11-28 9:21 ` Huang, Kai
2022-11-28 9:26 ` David Hildenbrand
2022-11-28 9:50 ` Huang, Kai
2022-11-24 9:26 ` Peter Zijlstra
2022-11-24 10:02 ` Huang, Kai
2022-11-30 22:26 ` Dave Hansen
2022-11-21 0:26 ` [PATCH v7 11/20] x86/virt/tdx: Add placeholder to construct TDMRs to cover all TDX memory regions Kai Huang
2022-11-23 22:17 ` Dave Hansen
2022-11-24 9:51 ` Huang, Kai
2022-11-24 12:02 ` Huang, Kai
2022-11-28 15:59 ` Dave Hansen
2022-11-28 22:13 ` Huang, Kai
2022-11-28 22:19 ` Dave Hansen
2022-11-28 22:50 ` Huang, Kai
2022-12-07 11:47 ` Huang, Kai
2022-12-08 12:56 ` Huang, Kai
2022-12-08 14:58 ` Dave Hansen
2022-12-08 23:29 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 12/20] x86/virt/tdx: Create " Kai Huang
2022-11-23 22:41 ` Dave Hansen
2022-11-24 11:29 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 13/20] x86/virt/tdx: Allocate and set up PAMTs for TDMRs Kai Huang
2022-11-23 22:57 ` Dave Hansen
2022-11-24 11:46 ` Huang, Kai
2022-11-28 16:39 ` Dave Hansen
2022-11-28 22:48 ` Huang, Kai
2022-11-28 22:56 ` Dave Hansen
2022-11-28 23:14 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 14/20] x86/virt/tdx: Set up reserved areas for all TDMRs Kai Huang
2022-11-23 23:39 ` Dave Hansen
2022-11-28 9:14 ` Huang, Kai
2022-11-28 13:18 ` Dave Hansen
2022-11-28 22:24 ` Huang, Kai
2022-11-28 22:58 ` Dave Hansen
2022-11-28 23:10 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 15/20] x86/virt/tdx: Reserve TDX module global KeyID Kai Huang
2022-11-23 23:40 ` Dave Hansen
2022-11-24 22:39 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 16/20] x86/virt/tdx: Configure TDX module with TDMRs and " Kai Huang
2022-11-23 23:56 ` Dave Hansen
2022-11-25 0:59 ` Huang, Kai
2022-11-25 1:18 ` Dave Hansen
2022-11-25 1:44 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 17/20] x86/virt/tdx: Configure global KeyID on all packages Kai Huang
2022-11-24 0:28 ` Dave Hansen
2022-11-24 22:28 ` Huang, Kai
2022-11-25 0:08 ` Huang, Kai
2022-11-30 3:35 ` Binbin Wu
2022-11-30 8:34 ` Huang, Kai
2022-11-30 14:04 ` kirill.shutemov
2022-11-30 15:13 ` Dave Hansen
2022-11-30 20:17 ` Huang, Kai
2022-11-30 17:37 ` Dave Hansen
2022-11-21 0:26 ` [PATCH v7 18/20] x86/virt/tdx: Initialize all TDMRs Kai Huang
2022-11-24 0:42 ` Dave Hansen
2022-11-25 2:27 ` Huang, Kai
2022-11-21 0:26 ` [PATCH v7 19/20] x86/virt/tdx: Flush cache in kexec() when TDX is enabled Kai Huang
2022-11-21 0:26 ` [PATCH v7 20/20] Documentation/x86: Add documentation for TDX host support Kai Huang
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