Messages in this thread Patch in this message | | | From | Kuppuswamy Sathyanarayanan <> | Subject | [RFC v2-fix-v1 1/1] x86/tdx: Add helper to do MapGPA hypercall | Date | Wed, 26 May 2021 21:56:38 -0700 |
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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
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@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> ---
Changes since RFC v2: * Renamed tdg_map_gpa() to tdx_hcall_gpa_intent(). * Fixed commit log and comments as per review comments.
arch/x86/include/asm/tdx.h | 17 +++++++++++++++++ arch/x86/kernel/tdx.c | 24 ++++++++++++++++++++++++ 2 files changed, 41 insertions(+)
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index a93528246595..eb9fa5f4d0e3 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -7,6 +7,15 @@ #ifndef __ASSEMBLY__ +/* + * 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 #include <asm/cpufeature.h> @@ -119,6 +128,8 @@ do { \ #endif 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); #else // !CONFIG_INTEL_TDX_GUEST @@ -143,6 +154,12 @@ 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 0c8b10b78f32..a8ebd2d10093 100644 --- a/arch/x86/kernel/tdx.c +++ b/arch/x86/kernel/tdx.c @@ -16,6 +16,9 @@ #define TDINFO 1 #define TDGETVEINFO 3 +/* TDX hypercall Leaf IDs */ +#define TDVMCALL_MAP_GPA 0x10001 + #define VE_GET_IO_TYPE(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) @@ -122,6 +125,27 @@ 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); + + return ret ? -EIO : 0; +} + static __cpuidle void tdg_halt(void) { u64 ret; -- 2.25.1
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