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x86/sev-es: Compile early handler code into kernel image
Setup sev-es.c and include the code from the pre-decompression stage to also build it into the image of the running kernel. Temporarily add __maybe_unused annotations to avoid build warnings until the functions get used. [ bp: Use the non-tracing rd/wrmsr variants because: vmlinux.o: warning: objtool: __sev_es_nmi_complete()+0x11f: \ call to do_trace_write_msr() leaves .noinstr.text section as __sev_es_nmi_complete() is noinstr due to being called from the NMI handler exc_nmi(). ] Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-39-joro@8bytes.org
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Joerg Roedel
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Borislav Petkov
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Sep 9, 2020
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,163 @@ | ||
| // SPDX-License-Identifier: GPL-2.0-only | ||
| /* | ||
| * AMD Memory Encryption Support | ||
| * | ||
| * Copyright (C) 2019 SUSE | ||
| * | ||
| * Author: Joerg Roedel <jroedel@suse.de> | ||
| */ | ||
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| #include <linux/kernel.h> | ||
| #include <linux/mm.h> | ||
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| #include <asm/sev-es.h> | ||
| #include <asm/insn-eval.h> | ||
| #include <asm/fpu/internal.h> | ||
| #include <asm/processor.h> | ||
| #include <asm/trap_pf.h> | ||
| #include <asm/trapnr.h> | ||
| #include <asm/svm.h> | ||
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| static inline u64 sev_es_rd_ghcb_msr(void) | ||
| { | ||
| return __rdmsr(MSR_AMD64_SEV_ES_GHCB); | ||
| } | ||
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| static inline void sev_es_wr_ghcb_msr(u64 val) | ||
| { | ||
| u32 low, high; | ||
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| low = (u32)(val); | ||
| high = (u32)(val >> 32); | ||
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| native_wrmsr(MSR_AMD64_SEV_ES_GHCB, low, high); | ||
| } | ||
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| static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt, | ||
| unsigned char *buffer) | ||
| { | ||
| return copy_from_kernel_nofault(buffer, (unsigned char *)ctxt->regs->ip, MAX_INSN_SIZE); | ||
| } | ||
|
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| static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt) | ||
| { | ||
| char buffer[MAX_INSN_SIZE]; | ||
| enum es_result ret; | ||
| int res; | ||
|
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| res = vc_fetch_insn_kernel(ctxt, buffer); | ||
| if (unlikely(res == -EFAULT)) { | ||
| ctxt->fi.vector = X86_TRAP_PF; | ||
| ctxt->fi.error_code = 0; | ||
| ctxt->fi.cr2 = ctxt->regs->ip; | ||
| return ES_EXCEPTION; | ||
| } | ||
|
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| insn_init(&ctxt->insn, buffer, MAX_INSN_SIZE - res, 1); | ||
| insn_get_length(&ctxt->insn); | ||
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| ret = ctxt->insn.immediate.got ? ES_OK : ES_DECODE_FAILED; | ||
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| return ret; | ||
| } | ||
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| static enum es_result vc_write_mem(struct es_em_ctxt *ctxt, | ||
| char *dst, char *buf, size_t size) | ||
| { | ||
| unsigned long error_code = X86_PF_PROT | X86_PF_WRITE; | ||
| char __user *target = (char __user *)dst; | ||
| u64 d8; | ||
| u32 d4; | ||
| u16 d2; | ||
| u8 d1; | ||
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| switch (size) { | ||
| case 1: | ||
| memcpy(&d1, buf, 1); | ||
| if (put_user(d1, target)) | ||
| goto fault; | ||
| break; | ||
| case 2: | ||
| memcpy(&d2, buf, 2); | ||
| if (put_user(d2, target)) | ||
| goto fault; | ||
| break; | ||
| case 4: | ||
| memcpy(&d4, buf, 4); | ||
| if (put_user(d4, target)) | ||
| goto fault; | ||
| break; | ||
| case 8: | ||
| memcpy(&d8, buf, 8); | ||
| if (put_user(d8, target)) | ||
| goto fault; | ||
| break; | ||
| default: | ||
| WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size); | ||
| return ES_UNSUPPORTED; | ||
| } | ||
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| return ES_OK; | ||
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| fault: | ||
| if (user_mode(ctxt->regs)) | ||
| error_code |= X86_PF_USER; | ||
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| ctxt->fi.vector = X86_TRAP_PF; | ||
| ctxt->fi.error_code = error_code; | ||
| ctxt->fi.cr2 = (unsigned long)dst; | ||
|
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| return ES_EXCEPTION; | ||
| } | ||
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| static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, | ||
| char *src, char *buf, size_t size) | ||
| { | ||
| unsigned long error_code = X86_PF_PROT; | ||
| char __user *s = (char __user *)src; | ||
| u64 d8; | ||
| u32 d4; | ||
| u16 d2; | ||
| u8 d1; | ||
|
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| switch (size) { | ||
| case 1: | ||
| if (get_user(d1, s)) | ||
| goto fault; | ||
| memcpy(buf, &d1, 1); | ||
| break; | ||
| case 2: | ||
| if (get_user(d2, s)) | ||
| goto fault; | ||
| memcpy(buf, &d2, 2); | ||
| break; | ||
| case 4: | ||
| if (get_user(d4, s)) | ||
| goto fault; | ||
| memcpy(buf, &d4, 4); | ||
| break; | ||
| case 8: | ||
| if (get_user(d8, s)) | ||
| goto fault; | ||
| memcpy(buf, &d8, 8); | ||
| break; | ||
| default: | ||
| WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size); | ||
| return ES_UNSUPPORTED; | ||
| } | ||
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| return ES_OK; | ||
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| fault: | ||
| if (user_mode(ctxt->regs)) | ||
| error_code |= X86_PF_USER; | ||
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| ctxt->fi.vector = X86_TRAP_PF; | ||
| ctxt->fi.error_code = error_code; | ||
| ctxt->fi.cr2 = (unsigned long)src; | ||
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| return ES_EXCEPTION; | ||
| } | ||
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| /* Include code shared with pre-decompression boot stage */ | ||
| #include "sev-es-shared.c" |