4c5b9aac6c
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> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20220405232939.73860-17-kirill.shutemov@linux.intel.com
77 lines
1.4 KiB
C
77 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "../cpuflags.h"
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#include "../string.h"
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#include "../io.h"
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#include "error.h"
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#include <vdso/limits.h>
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#include <uapi/asm/vmx.h>
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#include <asm/shared/tdx.h>
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/* Called from __tdx_hypercall() for unrecoverable failure */
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void __tdx_hypercall_failed(void)
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{
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error("TDVMCALL failed. TDX module bug?");
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}
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static inline unsigned int tdx_io_in(int size, u16 port)
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{
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struct tdx_hypercall_args args = {
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.r10 = TDX_HYPERCALL_STANDARD,
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.r11 = EXIT_REASON_IO_INSTRUCTION,
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.r12 = size,
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.r13 = 0,
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.r14 = port,
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};
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if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT))
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return UINT_MAX;
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return args.r11;
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}
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static inline void tdx_io_out(int size, u16 port, u32 value)
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{
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struct tdx_hypercall_args args = {
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.r10 = TDX_HYPERCALL_STANDARD,
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.r11 = EXIT_REASON_IO_INSTRUCTION,
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.r12 = size,
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.r13 = 1,
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.r14 = port,
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.r15 = value,
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};
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__tdx_hypercall(&args, 0);
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}
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static inline u8 tdx_inb(u16 port)
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{
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return tdx_io_in(1, port);
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}
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static inline void tdx_outb(u8 value, u16 port)
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{
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tdx_io_out(1, port, value);
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}
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static inline void tdx_outw(u16 value, u16 port)
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{
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tdx_io_out(2, port, value);
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}
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void early_tdx_detect(void)
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{
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u32 eax, sig[3];
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cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2], &sig[1]);
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if (memcmp(TDX_IDENT, sig, sizeof(sig)))
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return;
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/* Use hypercalls instead of I/O instructions */
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pio_ops.f_inb = tdx_inb;
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pio_ops.f_outb = tdx_outb;
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pio_ops.f_outw = tdx_outw;
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}
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