The following commit has been merged into the x86/tdx branch of tip:
Commit-ID: 4c5b9aac6cade51aef64cc6ed67f2ad5acda9aed
Gitweb: https://git.kernel.org/tip/4c5b9aac6cade51aef64cc6ed67f2ad5acda9aed
Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 06 Apr 2022 02:29:25 +03:00
Committer: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Thu, 07 Apr 2022 08:27:52 -07:00
x86/boot: Port I/O: Add decompression-time support for TDX
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@xxxxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20220405232939.73860-17-kirill.shutemov@xxxxxxxxxxxxxxx
---
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 732f6b2..8fd0e6a 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 0000000..46d0495
--- /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 5f6d01a..918a760 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 8209ba9..e53f262 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 81a1ec1..7944fd1 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -3,17 +3,11 @@
#ifndef _ASM_X86_TDX_H
#define _ASM_X86_TDX_H
-#include <linux/bits.h>
#include <linux/init.h>
#include <linux/bits.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.
*
@@ -42,21 +36,6 @@ struct tdx_module_output {
};
/*
- * 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
* and not part of the TDX module/VMM ABI.
@@ -80,12 +59,6 @@ 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);
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