On 6/28/2022 5:53 AM, isaku.yamahata@xxxxxxxxx wrote:
From: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
TDX requires additional parameters for TDX VM for confidential execution to
protect its confidentiality of its memory contents and its CPU state from
any other software, including VMM. When creating guest TD VM before
creating vcpu, the number of vcpu, TSC frequency (that is same among
vcpus. and it can't be changed.) CPUIDs which is emulated by the TDX
module. It means guest can trust those CPUIDs. and sha384 values for
measurement.
Add new subcommand, KVM_TDX_INIT_VM, to pass parameters for TDX guest. It
assigns encryption key to the TDX guest for memory encryption. TDX
encrypts memory per-guest bases. It assigns device model passes per-VM
parameters for the TDX guest. The maximum number of vcpus, tsc frequency
(TDX guest has fised VM-wide TSC frequency. not per-vcpu. The TDX guest
can not change it.), attributes (production or debug), available extended
features (which is reflected into guest XCR0, IA32_XSS MSR), cpuids, sha384
measurements, and etc.
This subcommand is called before creating vcpu and KVM_SET_CPUID2, i.e.
cpuids configurations aren't available yet. So CPUIDs configuration values
needs to be passed in struct kvm_init_vm. It's device model responsibility
to make this cpuid config for KVM_TDX_INIT_VM and KVM_SET_CPUID2.
Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/include/asm/tdx.h | 3 +
arch/x86/include/uapi/asm/kvm.h | 33 +++++
arch/x86/kvm/vmx/tdx.c | 206 ++++++++++++++++++++++++++
arch/x86/kvm/vmx/tdx.h | 23 +++
tools/arch/x86/include/uapi/asm/kvm.h | 33 +++++
6 files changed, 300 insertions(+)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 342decc69649..81638987cdb9 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1338,6 +1338,8 @@ struct kvm_arch {
* the global KVM_MAX_VCPU_IDS may lead to significant memory waste.
*/
u32 max_vcpu_ids;
+
+ gfn_t gfn_shared_mask;
I think it's better to put in a seperate patch or the patch that
consumes it.
};
...
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 2a9dfd54189f..1273b60a1a00 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -438,6 +438,209 @@ int tdx_dev_ioctl(void __user *argp)
return 0;
}
+/*
+ * cpuid entry lookup in TDX cpuid config way.
+ * The difference is how to specify index(subleaves).
+ * Specify index to TDX_CPUID_NO_SUBLEAF for CPUID leaf with no-subleaves.
+ */
+static const struct kvm_cpuid_entry2 *tdx_find_cpuid_entry(
+ const struct kvm_cpuid2 *cpuid, u32 function, u32 index)
+{
+ int i;
+
+
superfluous line
+ /* In TDX CPU CONFIG, TDX_CPUID_NO_SUBLEAF means index = 0. */
+ if (index == TDX_CPUID_NO_SUBLEAF)
+ index = 0;
+
+ for (i = 0; i < cpuid->nent; i++) {
+ const struct kvm_cpuid_entry2 *e = &cpuid->entries[i];
+
+ if (e->function == function &&
+ (e->index == index ||
+ !(e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX)))
+ return e;
+ }
+ return NULL;
+}
no need for kvm_tdx->tsc_khz field. We have kvm->arch.default_tsc_khz.
It seems kvm_tdx->tsc_khz is not used in the following patches.
...
+
+ kvm_tdx->tsc_offset = td_tdcs_exec_read64(kvm_tdx, TD_TDCS_EXEC_TSC_OFFSET);
+ kvm_tdx->attributes = td_params->attributes;
+ kvm_tdx->xfam = td_params->xfam;
+ kvm_tdx->tsc_khz = TDX_TSC_25MHZ_TO_KHZ(td_params->tsc_frequency);
+ kvm->max_vcpus = td_params->max_vcpus;
+
+ if (td_params->exec_controls & TDX_EXEC_CONTROL_MAX_GPAW)
+ kvm->arch.gfn_shared_mask = gpa_to_gfn(BIT_ULL(51));
+ else
+ kvm->arch.gfn_shared_mask = gpa_to_gfn(BIT_ULL(47));
+
....
diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h
index a9ea3573be1b..779dfd683d66 100644
--- a/tools/arch/x86/include/uapi/asm/kvm.h
+++ b/tools/arch/x86/include/uapi/asm/kvm.h
@@ -531,6 +531,7 @@ struct kvm_pmu_event_filter {
/* Trust Domain eXtension sub-ioctl() commands. */
enum kvm_tdx_cmd_id {
KVM_TDX_CAPABILITIES = 0,
+ KVM_TDX_INIT_VM,
KVM_TDX_CMD_NR_MAX,
};
@@ -576,4 +577,36 @@ struct kvm_tdx_capabilities {
struct kvm_tdx_cpuid_config cpuid_configs[0];
};
+struct kvm_tdx_init_vm {
+ __u64 attributes;
+ __u32 max_vcpus;
+ __u32 tsc_khz;
it needs to align with arch/x86/include/uapi/asm/kvm.h that @tsc_khz
needs to be removed.
