From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
MapGPA hypercall is used by TDX guests to request VMM convert
the existing mapping of given GPA address range between
private/shared.
tdx_hcall_gpa_intent() is the wrapper used for making MapGPA
hypercall.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
Changes since v3:
* None
Changes since v1:
* Modified tdx_hcall_gpa_intent() to use _tdx_hypercall() instead of
tdx_hypercall().
arch/x86/include/asm/tdx.h | 18 ++++++++++++++++++
arch/x86/kernel/tdx.c | 25 +++++++++++++++++++++++++
2 files changed, 43 insertions(+)
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index 1e2a1c6a1898..665c8cf57d5b 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -56,6 +56,15 @@ struct ve_info {
u32 instr_info;
};
+/*
+ * Page mapping type enum. This is software construct not
+ * part of any hardware or VMM ABI.
+ */
+enum tdx_map_type {
+ TDX_MAP_PRIVATE,
+ TDX_MAP_SHARED,
+};
+
#ifdef CONFIG_INTEL_TDX_GUEST
void __init tdx_early_init(void);
@@ -79,6 +88,9 @@ bool tdg_early_handle_ve(struct pt_regs *regs);
extern phys_addr_t tdg_shared_mask(void);
+extern int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,
+ enum tdx_map_type map_type);
+
/*
* To support I/O port access in decompressor or early kernel init
* code, since #VE exception handler cannot be used, use paravirt
@@ -149,6 +161,12 @@ static inline bool tdg_early_handle_ve(struct pt_regs *regs) { return false; }
static inline phys_addr_t tdg_shared_mask(void) { return 0; }
+static inline int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,
+ enum tdx_map_type map_type)
+{
+ return -ENODEV;
+}
+
#endif /* CONFIG_INTEL_TDX_GUEST */
#ifdef CONFIG_INTEL_TDX_GUEST_KVM
diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
index d316fe33f52f..ccbad600a422 100644
--- a/arch/x86/kernel/tdx.c
+++ b/arch/x86/kernel/tdx.c
@@ -18,6 +18,9 @@
#define TDINFO 1
#define TDGETVEINFO 3
+/* TDX hypercall Leaf IDs */
+#define TDVMCALL_MAP_GPA 0x10001
+
#define VE_IS_IO_OUT(exit_qual) (((exit_qual) & 8) ? 0 : 1)
#define VE_GET_IO_SIZE(exit_qual) (((exit_qual) & 7) + 1)
#define VE_GET_PORT_NUM(exit_qual) ((exit_qual) >> 16)
@@ -97,6 +100,28 @@ static void tdg_get_info(void)
physical_mask &= ~tdg_shared_mask();
}
+/*
+ * Inform the VMM of the guest's intent for this physical page:
+ * shared with the VMM or private to the guest. The VMM is
+ * expected to change its mapping of the page in response.
+ *
+ * Note: shared->private conversions require further guest
+ * action to accept the page.
+ */
+int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,
+ enum tdx_map_type map_type)
+{
+ u64 ret;
+
+ if (map_type == TDX_MAP_SHARED)
+ gpa |= tdg_shared_mask();
+
+ ret = _tdx_hypercall(TDVMCALL_MAP_GPA, gpa, PAGE_SIZE * numpages, 0, 0,
+ NULL);
+
+ return ret ? -EIO : 0;
+}
+
static __cpuidle void tdg_halt(void)
{
u64 ret;
--
2.25.1
