Re: [PATCH v7 011/102] KVM: TDX: Initialize TDX module when loading kvm_intel.ko

[Kai Huang <kai.huang@intel.com>]

On Mon, 2022-06-27 at 14:53 -0700, isaku.yamahata@intel.com wrote:
> From: Isaku Yamahata <isaku.yamahata@intel.com>
> 
> To use TDX functionality, TDX module needs to be loaded and initialized.
> A TDX host patch series[1] implements the detection of the TDX module,
> tdx_detect() and its initialization, tdx_init().

"A TDX host patch series[1]" really isn't a commit message material.  You can
put it to the cover letter, but not here.

Also tdx_detect() is removed in latest code.

> 
> This patch is to call those functions, tdx_detect() and tdx_init(), when
> loading kvm_intel.ko.
> 
> Add a hook, kvm_arch_post_hardware_enable_setup, to module initialization
> while hardware is enabled, i.e. after hardware_enable_all() and before
> hardware_disable_all().  Because TDX requires all present CPUs to enable
> VMX (VMXON).
> 
> [1] https://lore.kernel.org/lkml/cover.1649219184.git.kai.huang@intel.com/
> 
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
>  arch/x86/include/asm/kvm_host.h |  1 +
>  arch/x86/kvm/vmx/main.c         | 11 ++++++
>  arch/x86/kvm/vmx/tdx.c          | 60 +++++++++++++++++++++++++++++++++
>  arch/x86/kvm/vmx/tdx.h          |  4 +++
>  arch/x86/kvm/x86.c              |  8 +++++
>  5 files changed, 84 insertions(+)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 62dec97f6607..aa11525500d3 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1639,6 +1639,7 @@ struct kvm_x86_init_ops {
>  	int (*cpu_has_kvm_support)(void);
>  	int (*disabled_by_bios)(void);
>  	int (*hardware_setup)(void);
> +	int (*post_hardware_enable_setup)(void);
>  	unsigned int (*handle_intel_pt_intr)(void);
>  
>  	struct kvm_x86_ops *runtime_ops;
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index 349534412216..ac788af17d92 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -23,6 +23,16 @@ static __init int vt_hardware_setup(void)
>  	return 0;
>  }
>  
> +static int __init vt_post_hardware_enable_setup(void)
> +{
> +	enable_tdx = enable_tdx && !tdx_module_setup();
> +	/*
> +	 * Even if it failed to initialize TDX module, conventional VMX is
> +	 * available.  Keep VMX usable.
> +	 */
> +	return 0;
> +}
> +
>  struct kvm_x86_ops vt_x86_ops __initdata = {
>  	.name = "kvm_intel",
>  
> @@ -165,6 +175,7 @@ struct kvm_x86_init_ops vt_init_ops __initdata = {
>  	.cpu_has_kvm_support = vmx_cpu_has_kvm_support,
>  	.disabled_by_bios = vmx_disabled_by_bios,
>  	.hardware_setup = vt_hardware_setup,
> +	.post_hardware_enable_setup = vt_post_hardware_enable_setup,
>  	.handle_intel_pt_intr = NULL,
>  
>  	.runtime_ops = &vt_x86_ops,
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index 2617389ef466..9cb36716b0f3 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -13,6 +13,66 @@
>  static u64 hkid_mask __ro_after_init;
>  static u8 hkid_start_pos __ro_after_init;
>  
> +#define TDX_MAX_NR_CPUID_CONFIGS					\
> +	((sizeof(struct tdsysinfo_struct) -				\
> +		offsetof(struct tdsysinfo_struct, cpuid_configs))	\
> +		/ sizeof(struct tdx_cpuid_config))
> +
> +struct tdx_capabilities {
> +	u8 tdcs_nr_pages;
> +	u8 tdvpx_nr_pages;
> +
> +	u64 attrs_fixed0;
> +	u64 attrs_fixed1;
> +	u64 xfam_fixed0;
> +	u64 xfam_fixed1;
> +
> +	u32 nr_cpuid_configs;
> +	struct tdx_cpuid_config cpuid_configs[TDX_MAX_NR_CPUID_CONFIGS];
> +};
> +
> +/* Capabilities of KVM + the TDX module. */
> +static struct tdx_capabilities tdx_caps;
> +
> +int __init tdx_module_setup(void)
> +{
> +	const struct tdsysinfo_struct *tdsysinfo;
> +	int ret = 0;
> +
> +	BUILD_BUG_ON(sizeof(*tdsysinfo) != 1024);
> +	BUILD_BUG_ON(TDX_MAX_NR_CPUID_CONFIGS != 37);
> +
> +	ret = tdx_init();
> +	if (ret) {
> +		pr_info("Failed to initialize TDX module.\n");
> +		return ret;
> +	}
> +
> +	tdsysinfo = tdx_get_sysinfo();
> +	if (tdsysinfo->num_cpuid_config > TDX_MAX_NR_CPUID_CONFIGS)
> +		return -EIO;
> +
> +	tdx_caps = (struct tdx_capabilities) {
> +		.tdcs_nr_pages = tdsysinfo->tdcs_base_size / PAGE_SIZE,
> +		/*
> +		 * TDVPS = TDVPR(4K page) + TDVPX(multiple 4K pages).
> +		 * -1 for TDVPR.
> +		 */
> +		.tdvpx_nr_pages = tdsysinfo->tdvps_base_size / PAGE_SIZE - 1,
> +		.attrs_fixed0 = tdsysinfo->attributes_fixed0,
> +		.attrs_fixed1 = tdsysinfo->attributes_fixed1,
> +		.xfam_fixed0 =	tdsysinfo->xfam_fixed0,
> +		.xfam_fixed1 = tdsysinfo->xfam_fixed1,
> +		.nr_cpuid_configs = tdsysinfo->num_cpuid_config,
> +	};
> +	if (!memcpy(tdx_caps.cpuid_configs, tdsysinfo->cpuid_configs,
> +			tdsysinfo->num_cpuid_config *
> +			sizeof(struct tdx_cpuid_config)))
> +		return -EIO;
> +
> +	return 0;
> +}
> +
>  int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops)
>  {
>  	u32 max_pa;
> diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
> index 060bf48ec3d6..54d7a26ed9ee 100644
> --- a/arch/x86/kvm/vmx/tdx.h
> +++ b/arch/x86/kvm/vmx/tdx.h
> @@ -3,6 +3,8 @@
>  #define __KVM_X86_TDX_H
>  
>  #ifdef CONFIG_INTEL_TDX_HOST
> +int tdx_module_setup(void);
> +
>  struct kvm_tdx {
>  	struct kvm kvm;
>  	/* TDX specific members follow. */
> @@ -37,6 +39,8 @@ static inline struct vcpu_tdx *to_tdx(struct kvm_vcpu *vcpu)
>  	return container_of(vcpu, struct vcpu_tdx, vcpu);
>  }
>  #else
> +static inline int tdx_module_setup(void) { return -ENODEV; };
> +
>  struct kvm_tdx {
>  	struct kvm kvm;
>  };
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 30af2bd0b4d5..fb7a33fbc136 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -11792,6 +11792,14 @@ int kvm_arch_hardware_setup(void *opaque)
>  	return 0;
>  }
>  
> +int kvm_arch_post_hardware_enable_setup(void *opaque)
> +{
> +	struct kvm_x86_init_ops *ops = opaque;
> +	if (ops->post_hardware_enable_setup)
> +		return ops->post_hardware_enable_setup();
> +	return 0;
> +}
> +

Where is this kvm_arch_post_hardware_enable_setup() called?

Shouldn't the code change which calls it be part of this patch?

>  void kvm_arch_hardware_unsetup(void)
>  {
>  	kvm_unregister_perf_callbacks();