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

isaku.yamahata
2022-06-27T21:55:36Z

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().

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;
+}
+
void kvm_arch_hardware_unsetup(void)
{
kvm_unregister_perf_callbacks();
--
2.25.1