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[RFC PATCH v4 11/36] i386/tdx: Initialize TDX before creating TD vcpus
From: |
Xiaoyao Li |
Subject: |
[RFC PATCH v4 11/36] i386/tdx: Initialize TDX before creating TD vcpus |
Date: |
Thu, 12 May 2022 11:17:38 +0800 |
Invoke KVM_TDX_INIT in kvm_arch_pre_create_vcpu() that KVM_TDX_INIT
configures global TD state, e.g. the canonical CPUID config, and must
be executed prior to creating vCPUs.
Use kvm_x86_arch_cpuid() to setup the CPUID settings for TDX VM and
tie x86cpu->enable_pmu with TD's attributes.
Note, this doesn't address the fact that QEMU may change the CPUID
configuration when creating vCPUs, i.e. punts on refactoring QEMU to
provide a stable CPUID config prior to kvm_arch_init().
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
accel/kvm/kvm-all.c | 9 ++++++++-
target/i386/kvm/kvm.c | 8 ++++++++
target/i386/kvm/tdx-stub.c | 5 +++++
target/i386/kvm/tdx.c | 35 +++++++++++++++++++++++++++++++++++
target/i386/kvm/tdx.h | 4 ++++
5 files changed, 60 insertions(+), 1 deletion(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index e6fa9d23207a..88468878d181 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -470,10 +470,17 @@ int kvm_init_vcpu(CPUState *cpu, Error **errp)
trace_kvm_init_vcpu(cpu->cpu_index, kvm_arch_vcpu_id(cpu));
+ /*
+ * tdx_pre_create_vcpu() may call cpu_x86_cpuid(). It in turn may call
+ * kvm_vm_ioctl(). Set cpu->kvm_state in advance to avoid NULL pointer
+ * dereference.
+ */
+ cpu->kvm_state = s;
ret = kvm_arch_pre_create_vcpu(cpu);
if (ret < 0) {
error_setg_errno(errp, -ret,
"kvm_init_vcpu: kvm_arch_pre_create_vcpu() failed");
+ cpu->kvm_state = NULL;
goto err;
}
@@ -481,11 +488,11 @@ int kvm_init_vcpu(CPUState *cpu, Error **errp)
if (ret < 0) {
error_setg_errno(errp, -ret, "kvm_init_vcpu: kvm_get_vcpu failed
(%lu)",
kvm_arch_vcpu_id(cpu));
+ cpu->kvm_state = NULL;
goto err;
}
cpu->kvm_fd = ret;
- cpu->kvm_state = s;
cpu->vcpu_dirty = true;
cpu->dirty_pages = 0;
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 5be151e6499b..f2d7c3cf59ac 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -2175,6 +2175,14 @@ int kvm_arch_init_vcpu(CPUState *cs)
return r;
}
+int kvm_arch_pre_create_vcpu(CPUState *cpu)
+{
+ if (is_tdx_vm())
+ return tdx_pre_create_vcpu(cpu);
+
+ return 0;
+}
+
int kvm_arch_destroy_vcpu(CPUState *cs)
{
X86CPU *cpu = X86_CPU(cs);
diff --git a/target/i386/kvm/tdx-stub.c b/target/i386/kvm/tdx-stub.c
index 1df24735201e..2871de9d7b56 100644
--- a/target/i386/kvm/tdx-stub.c
+++ b/target/i386/kvm/tdx-stub.c
@@ -7,3 +7,8 @@ int tdx_kvm_init(MachineState *ms, Error **errp)
{
return -EINVAL;
}
+
+int tdx_pre_create_vcpu(CPUState *cpu)
+{
+ return -EINVAL;
+}
diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 6e3b15ba8a4a..3472b59c2dbb 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -18,6 +18,7 @@
#include "sysemu/kvm.h"
#include "hw/i386/x86.h"
+#include "kvm_i386.h"
#include "tdx.h"
#define TDX_SUPPORTED_KVM_FEATURES ((1ULL << KVM_FEATURE_NOP_IO_DELAY) | \
@@ -165,6 +166,38 @@ void tdx_get_supported_cpuid(uint32_t function, uint32_t
index, int reg,
}
}
+int tdx_pre_create_vcpu(CPUState *cpu)
+{
+ MachineState *ms = MACHINE(qdev_get_machine());
+ X86CPU *x86cpu = X86_CPU(cpu);
+ CPUX86State *env = &x86cpu->env;
+ struct kvm_tdx_init_vm init_vm;
+ int r = 0;
+
+ qemu_mutex_lock(&tdx_guest->lock);
+ if (tdx_guest->initialized) {
+ goto out;
+ }
+
+ memset(&init_vm, 0, sizeof(init_vm));
+ init_vm.cpuid.nent = kvm_x86_arch_cpuid(env, init_vm.entries, 0);
+
+ init_vm.attributes = tdx_guest->attributes;
+ init_vm.max_vcpus = ms->smp.cpus;
+
+ r = tdx_vm_ioctl(KVM_TDX_INIT_VM, 0, &init_vm);
+ if (r < 0) {
+ error_report("KVM_TDX_INIT_VM failed %s", strerror(-r));
+ goto out;
+ }
+
+ tdx_guest->initialized = true;
+
+out:
+ qemu_mutex_unlock(&tdx_guest->lock);
+ return r;
+}
+
/* tdx guest */
OBJECT_DEFINE_TYPE_WITH_INTERFACES(TdxGuest,
tdx_guest,
@@ -177,6 +210,8 @@ static void tdx_guest_init(Object *obj)
{
TdxGuest *tdx = TDX_GUEST(obj);
+ qemu_mutex_init(&tdx->lock);
+
tdx->attributes = 0;
}
diff --git a/target/i386/kvm/tdx.h b/target/i386/kvm/tdx.h
index 06599b65b827..46a24ee8c7cc 100644
--- a/target/i386/kvm/tdx.h
+++ b/target/i386/kvm/tdx.h
@@ -17,6 +17,9 @@ typedef struct TdxGuestClass {
typedef struct TdxGuest {
ConfidentialGuestSupport parent_obj;
+ QemuMutex lock;
+
+ bool initialized;
uint64_t attributes; /* TD attributes */
} TdxGuest;
@@ -29,5 +32,6 @@ bool is_tdx_vm(void);
int tdx_kvm_init(MachineState *ms, Error **errp);
void tdx_get_supported_cpuid(uint32_t function, uint32_t index, int reg,
uint32_t *ret);
+int tdx_pre_create_vcpu(CPUState *cpu);
#endif /* QEMU_I386_TDX_H */
--
2.27.0