[PATCH v19 006/130] x86/virt/tdx: Export TDX KeyID information

isaku.yamahata
2024-02-26T08:27:39Z

From: Kai Huang <kai.huang@intel.com>

Each TDX guest must be protected by its own unique TDX KeyID. KVM will
need to tell the TDX module the unique KeyID for a TDX guest when KVM
creates it.

Export the TDX KeyID range that can be used by TDX guests for KVM to
use. KVM can then manage these KeyIDs and assign one for each TDX guest
when it is created.

Each TDX guest has a root control structure called "Trust Domain Root"
(TDR). Unlike the rest of the TDX guest, the TDR is protected by the
TDX global KeyID. When tearing down the TDR, KVM will need to pass the
TDX global KeyID explicitly to the TDX module to flush cache associated
to the TDR.

Also export the TDX global KeyID for KVM to tear down the TDR.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
arch/x86/include/asm/tdx.h | 5 +++++
arch/x86/virt/vmx/tdx/tdx.c | 11 ++++++++---
2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index 709b9483f9e4..16be3a1e4916 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -88,6 +88,11 @@ static inline long tdx_kvm_hypercall(unsigned int nr, unsigned long p1,
#endif /* CONFIG_INTEL_TDX_GUEST && CONFIG_KVM_GUEST */

#ifdef CONFIG_INTEL_TDX_HOST
+
+extern u32 tdx_global_keyid;
+extern u32 tdx_guest_keyid_start;
+extern u32 tdx_nr_guest_keyids;
+
u64 __seamcall(u64 fn, struct tdx_module_args *args);
u64 __seamcall_ret(u64 fn, struct tdx_module_args *args);
u64 __seamcall_saved_ret(u64 fn, struct tdx_module_args *args);
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index dc21310776ab..d2b8f079a637 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -39,9 +39,14 @@
#include <asm/mce.h>
#include "tdx.h"

-static u32 tdx_global_keyid __ro_after_init;
-static u32 tdx_guest_keyid_start __ro_after_init;
-static u32 tdx_nr_guest_keyids __ro_after_init;
+u32 tdx_global_keyid __ro_after_init;
+EXPORT_SYMBOL_GPL(tdx_global_keyid);
+
+u32 tdx_guest_keyid_start __ro_after_init;
+EXPORT_SYMBOL_GPL(tdx_guest_keyid_start);
+
+u32 tdx_nr_guest_keyids __ro_after_init;
+EXPORT_SYMBOL_GPL(tdx_nr_guest_keyids);

static DEFINE_PER_CPU(bool, tdx_lp_initialized);

--
2.25.1