mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
synced 2026-04-18 03:23:53 -04:00
37dbd78f98
Both the decompressor and the core kernel implement an early #VC handler, which only deals with CPUID instructions, and full featured one, which can handle any #VC exception. The former communicates with the hypervisor using the MSR based protocol, whereas the latter uses a shared GHCB page, which is configured a bit later during the boot, when the kernel runs from its ordinary virtual mapping, rather than the 1:1 mapping that the startup code uses. Accessing this shared GHCB page from the core kernel's startup code is problematic, because it involves converting the GHCB address provided by the caller to a physical address. In the startup code, virtual to physical address translations are problematic, given that the virtual address might be a 1:1 mapped address, and such translations should therefore be avoided. This means that exposing startup code dealing with the GHCB to callers that execute from the ordinary kernel virtual mapping should be avoided too. So move all GHCB page based communication out of the startup code, now that all communication occurring before the kernel virtual mapping is up relies on the MSR protocol only. As an exception, add a flag representing the need to apply the coherency fix in order to avoid exporting CPUID* helpers because of the code running too early for the *cpu_has* infrastructure. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250828102202.1849035-29-ardb+git@google.com
138 lines
2.7 KiB
C
138 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
|
|
#include "misc.h"
|
|
#include "error.h"
|
|
#include "sev.h"
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/string.h>
|
|
#include <asm/insn.h>
|
|
#include <asm/pgtable_types.h>
|
|
#include <asm/ptrace.h>
|
|
#include <asm/sev.h>
|
|
#include <asm/trapnr.h>
|
|
#include <asm/trap_pf.h>
|
|
#include <asm/fpu/xcr.h>
|
|
|
|
#define __BOOT_COMPRESSED
|
|
#undef __init
|
|
#define __init
|
|
|
|
/* Basic instruction decoding support needed */
|
|
#include "../../lib/inat.c"
|
|
#include "../../lib/insn.c"
|
|
|
|
/*
|
|
* Copy a version of this function here - insn-eval.c can't be used in
|
|
* pre-decompression code.
|
|
*/
|
|
bool insn_has_rep_prefix(struct insn *insn)
|
|
{
|
|
insn_byte_t p;
|
|
int i;
|
|
|
|
insn_get_prefixes(insn);
|
|
|
|
for_each_insn_prefix(insn, i, p) {
|
|
if (p == 0xf2 || p == 0xf3)
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
|
|
{
|
|
char buffer[MAX_INSN_SIZE];
|
|
int ret;
|
|
|
|
memcpy(buffer, (unsigned char *)ctxt->regs->ip, MAX_INSN_SIZE);
|
|
|
|
ret = insn_decode(&ctxt->insn, buffer, MAX_INSN_SIZE, INSN_MODE_64);
|
|
if (ret < 0)
|
|
return ES_DECODE_FAILED;
|
|
|
|
return ES_OK;
|
|
}
|
|
|
|
extern void sev_insn_decode_init(void) __alias(inat_init_tables);
|
|
|
|
/*
|
|
* Only a dummy for insn_get_seg_base() - Early boot-code is 64bit only and
|
|
* doesn't use segments.
|
|
*/
|
|
static unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx)
|
|
{
|
|
return 0UL;
|
|
}
|
|
|
|
static enum es_result vc_write_mem(struct es_em_ctxt *ctxt,
|
|
void *dst, char *buf, size_t size)
|
|
{
|
|
memcpy(dst, buf, size);
|
|
|
|
return ES_OK;
|
|
}
|
|
|
|
static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
|
|
void *src, char *buf, size_t size)
|
|
{
|
|
memcpy(buf, src, size);
|
|
|
|
return ES_OK;
|
|
}
|
|
|
|
static enum es_result vc_ioio_check(struct es_em_ctxt *ctxt, u16 port, size_t size)
|
|
{
|
|
return ES_OK;
|
|
}
|
|
|
|
static bool fault_in_kernel_space(unsigned long address)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
#define sev_printk(fmt, ...)
|
|
|
|
#include "../../coco/sev/vc-shared.c"
|
|
|
|
void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
|
|
{
|
|
struct es_em_ctxt ctxt;
|
|
enum es_result result;
|
|
|
|
if (!boot_ghcb && !early_setup_ghcb())
|
|
sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
|
|
|
|
vc_ghcb_invalidate(boot_ghcb);
|
|
result = vc_init_em_ctxt(&ctxt, regs, exit_code);
|
|
if (result != ES_OK)
|
|
goto finish;
|
|
|
|
result = vc_check_opcode_bytes(&ctxt, exit_code);
|
|
if (result != ES_OK)
|
|
goto finish;
|
|
|
|
switch (exit_code) {
|
|
case SVM_EXIT_RDTSC:
|
|
case SVM_EXIT_RDTSCP:
|
|
result = vc_handle_rdtsc(boot_ghcb, &ctxt, exit_code);
|
|
break;
|
|
case SVM_EXIT_IOIO:
|
|
result = vc_handle_ioio(boot_ghcb, &ctxt);
|
|
break;
|
|
case SVM_EXIT_CPUID:
|
|
result = vc_handle_cpuid(boot_ghcb, &ctxt);
|
|
break;
|
|
default:
|
|
result = ES_UNSUPPORTED;
|
|
break;
|
|
}
|
|
|
|
finish:
|
|
if (result == ES_OK)
|
|
vc_finish_insn(&ctxt);
|
|
else if (result != ES_RETRY)
|
|
sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
|
|
}
|