From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Several user ret MSRs are clobbered on TD exit. Restore those values on
TD exit and before returning to ring 3.
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
arch/x86/kvm/vmx/tdx.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 54be5be1a06c..c1366aac7d96 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -550,6 +550,28 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
vcpu->kvm->vm_bugged = true;
}
+struct tdx_uret_msr {
+ u32 msr;
+ unsigned int slot;
+ u64 defval;
+};
+
+static struct tdx_uret_msr tdx_uret_msrs[] = {
+ {.msr = MSR_SYSCALL_MASK,},
+ {.msr = MSR_STAR,},
+ {.msr = MSR_LSTAR,},
+ {.msr = MSR_TSC_AUX,},
+};
+
+static void tdx_user_return_update_cache(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(tdx_uret_msrs); i++)
+ kvm_user_return_update_cache(tdx_uret_msrs[i].slot,
+ tdx_uret_msrs[i].defval);
+}
+
static void tdx_restore_host_xsave_state(struct kvm_vcpu *vcpu)
{
struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
@@ -589,6 +611,7 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu)
tdx_vcpu_enter_exit(vcpu, tdx);
+ tdx_user_return_update_cache();
tdx_restore_host_xsave_state(vcpu);
tdx->host_state_need_restore = true;
@@ -1371,6 +1394,16 @@ static int __init __tdx_hardware_setup(struct kvm_x86_ops *x86_ops)
if (WARN_ON_ONCE(x86_ops->tlb_remote_flush))
return -EIO;
+ for (i = 0; i < ARRAY_SIZE(tdx_uret_msrs); i++) {
+ tdx_uret_msrs[i].slot = kvm_find_user_return_msr(tdx_uret_msrs[i].msr);
+ if (tdx_uret_msrs[i].slot == -1) {
+ /* If any MSR isn't supported, it is a KVM bug */
+ pr_err("MSR %x isn't included by kvm_find_user_return_msr\n",
+ tdx_uret_msrs[i].msr);
+ return -EIO;
+ }
+ }
+
max_pkgs = topology_max_packages();
tdx_mng_key_config_lock = kcalloc(max_pkgs, sizeof(*tdx_mng_key_config_lock),
GFP_KERNEL);
--
2.25.1
