Messages in this thread Patch in this message | | | From | "Kirill A. Shutemov" <> | Subject | [PATCHv7.1 16/30] x86/boot: Port I/O: add decompression-time support for TDX | Date | Fri, 18 Mar 2022 19:05:14 +0300 |
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Port I/O instructions trigger #VE in the TDX environment. In response to the exception, kernel emulates these instructions using hypercalls.
But during early boot, on the decompression stage, it is cumbersome to deal with #VE. It is cleaner to go to hypercalls directly, bypassing #VE handling.
Hook up TDX-specific port I/O helpers if booting in TDX environment.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> --- v7.1: - Explicitly use pio_ops when override port I/O callbacks --- arch/x86/boot/compressed/Makefile | 2 +- arch/x86/boot/compressed/tdcall.S | 3 ++ arch/x86/boot/compressed/tdx.c | 61 +++++++++++++++++++++++++++++++ arch/x86/include/asm/shared/tdx.h | 32 ++++++++++++++++ arch/x86/include/asm/tdx.h | 27 -------------- 5 files changed, 97 insertions(+), 28 deletions(-) create mode 100644 arch/x86/boot/compressed/tdcall.S
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 732f6b21ecbd..8fd0e6ae2e1f 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -101,7 +101,7 @@ ifdef CONFIG_X86_64 endif vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o -vmlinux-objs-$(CONFIG_INTEL_TDX_GUEST) += $(obj)/tdx.o +vmlinux-objs-$(CONFIG_INTEL_TDX_GUEST) += $(obj)/tdx.o $(obj)/tdcall.o vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o efi-obj-$(CONFIG_EFI_STUB) = $(objtree)/drivers/firmware/efi/libstub/lib.a diff --git a/arch/x86/boot/compressed/tdcall.S b/arch/x86/boot/compressed/tdcall.S new file mode 100644 index 000000000000..46d0495e0d3a --- /dev/null +++ b/arch/x86/boot/compressed/tdcall.S @@ -0,0 +1,3 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include "../../coco/tdx/tdcall.S" diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c index 5f6d01a2f1f4..918a7606f53c 100644 --- a/arch/x86/boot/compressed/tdx.c +++ b/arch/x86/boot/compressed/tdx.c @@ -2,9 +2,65 @@ #include "../cpuflags.h" #include "../string.h" +#include "../io.h" +#include "error.h" + +#include <vdso/limits.h> +#include <uapi/asm/vmx.h> #include <asm/shared/tdx.h> +/* Called from __tdx_hypercall() for unrecoverable failure */ +void __tdx_hypercall_failed(void) +{ + error("TDVMCALL failed. TDX module bug?"); +} + +static inline unsigned int tdx_io_in(int size, u16 port) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = EXIT_REASON_IO_INSTRUCTION, + .r12 = size, + .r13 = 0, + .r14 = port, + }; + + if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT)) + return UINT_MAX; + + return args.r11; +} + +static inline void tdx_io_out(int size, u16 port, u32 value) +{ + struct tdx_hypercall_args args = { + .r10 = TDX_HYPERCALL_STANDARD, + .r11 = EXIT_REASON_IO_INSTRUCTION, + .r12 = size, + .r13 = 1, + .r14 = port, + .r15 = value, + }; + + __tdx_hypercall(&args, 0); +} + +static inline u8 tdx_inb(u16 port) +{ + return tdx_io_in(1, port); +} + +static inline void tdx_outb(u8 value, u16 port) +{ + tdx_io_out(1, port, value); +} + +static inline void tdx_outw(u16 value, u16 port) +{ + tdx_io_out(2, port, value); +} + void early_tdx_detect(void) { u32 eax, sig[3]; @@ -13,4 +69,9 @@ void early_tdx_detect(void) if (memcmp(TDX_IDENT, sig, sizeof(sig))) return; + + /* Use hypercalls instead of I/O instructions */ + pio_ops.f_inb = tdx_inb; + pio_ops.f_outb = tdx_outb; + pio_ops.f_outw = tdx_outw; } diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h index 8209ba9ffe1a..e53f26228fbb 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -2,7 +2,39 @@ #ifndef _ASM_X86_SHARED_TDX_H #define _ASM_X86_SHARED_TDX_H +#include <linux/bits.h> +#include <linux/types.h> + +#define TDX_HYPERCALL_STANDARD 0 + +#define TDX_HCALL_HAS_OUTPUT BIT(0) +#define TDX_HCALL_ISSUE_STI BIT(1) + #define TDX_CPUID_LEAF_ID 0x21 #define TDX_IDENT "IntelTDX " +#ifndef __ASSEMBLY__ + +/* + * Used in __tdx_hypercall() to pass down and get back registers' values of + * the TDCALL instruction when requesting services from the VMM. + * + * This is a software only structure and not part of the TDX module/VMM ABI. + */ +struct tdx_hypercall_args { + u64 r10; + u64 r11; + u64 r12; + u64 r13; + u64 r14; + u64 r15; +}; + +/* Used to request services from the VMM */ +u64 __tdx_hypercall(struct tdx_hypercall_args *args, unsigned long flags); + +/* Called from __tdx_hypercall() for unrecoverable failure */ +void __tdx_hypercall_failed(void); + +#endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_SHARED_TDX_H */ diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index ca23adaa6681..1093a5e5f446 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -3,16 +3,10 @@ #ifndef _ASM_X86_TDX_H #define _ASM_X86_TDX_H -#include <linux/bits.h> #include <linux/init.h> #include <asm/ptrace.h> #include <asm/shared/tdx.h> -#define TDX_HYPERCALL_STANDARD 0 - -#define TDX_HCALL_HAS_OUTPUT BIT(0) -#define TDX_HCALL_ISSUE_STI BIT(1) - /* * SW-defined error codes. * @@ -40,21 +34,6 @@ struct tdx_module_output { u64 r11; }; -/* - * Used in __tdx_hypercall() to pass down and get back registers' values of - * the TDCALL instruction when requesting services from the VMM. - * - * This is a software only structure and not part of the TDX module/VMM ABI. - */ -struct tdx_hypercall_args { - u64 r10; - u64 r11; - u64 r12; - u64 r13; - u64 r14; - u64 r15; -}; - /* * Used by the #VE exception handler to gather the #VE exception * info from the TDX module. This is a software only structure @@ -79,12 +58,6 @@ void __init tdx_early_init(void); u64 __tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, struct tdx_module_output *out); -/* Used to request services from the VMM */ -u64 __tdx_hypercall(struct tdx_hypercall_args *args, unsigned long flags); - -/* Called from __tdx_hypercall() for unrecoverable failure */ -void __tdx_hypercall_failed(void); - void tdx_get_ve_info(struct ve_info *ve); bool tdx_handle_virt_exception(struct pt_regs *regs, struct ve_info *ve); -- 2.34.1
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