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authorKonstantin Belousov <kib@FreeBSD.org>2026-05-27 08:21:10 +0000
committerKonstantin Belousov <kib@FreeBSD.org>2026-05-28 17:26:56 +0000
commit0a02a47fd94a8326e84ac0a6cb857342b59671f8 (patch)
tree25ffa502b46a021eb113e7487e05da76c5b31afb
parent95fc64cc29fb4cddc7cad093cfa32587a623f560 (diff)
x86: for wrmsr_early_safe(), catch all exceptions, not only #GP
Reviewed by: olce Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D57264
-rw-r--r--sys/amd64/amd64/machdep.c24
-rw-r--r--sys/amd64/amd64/support.S7
2 files changed, 18 insertions, 13 deletions
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index db2fd5927f7f..8df4868f5312 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1827,29 +1827,35 @@ wrmsr_early_safe_start(void)
{
struct region_descriptor efi_idt;
struct gate_descriptor *gpf_descr;
+ int i;
sidt(&wrmsr_early_safe_orig_efi_idt);
efi_idt.rd_limit = 32 * sizeof(idt0[0]);
efi_idt.rd_base = (uintptr_t)idt0;
lidt(&efi_idt);
- gpf_descr = &idt0[IDT_GP];
- gpf_descr->gd_looffset = (uintptr_t)wrmsr_early_safe_gp_handler;
- gpf_descr->gd_hioffset = (uintptr_t)wrmsr_early_safe_gp_handler >> 16;
- gpf_descr->gd_selector = rcs();
- gpf_descr->gd_type = SDT_SYSTGT;
- gpf_descr->gd_p = 1;
+ /* Setup handler for all possible exceptions. */
+ for (i = 0; i < 32; i++) {
+ gpf_descr = &idt0[i];
+ gpf_descr->gd_looffset =
+ (uintptr_t)wrmsr_early_safe_gp_handler;
+ gpf_descr->gd_hioffset =
+ (uintptr_t)wrmsr_early_safe_gp_handler >> 16;
+ gpf_descr->gd_selector = rcs();
+ gpf_descr->gd_type = SDT_SYSTGT;
+ gpf_descr->gd_p = 1;
+ }
}
void
wrmsr_early_safe_end(void)
{
- struct gate_descriptor *gpf_descr;
+ int i;
lidt(&wrmsr_early_safe_orig_efi_idt);
- gpf_descr = &idt0[IDT_GP];
- memset_early(gpf_descr, 0, sizeof(*gpf_descr));
+ for (i = 0; i < 32; i++)
+ memset_early(&idt0[i], 0, sizeof(idt0[0]));
}
int
diff --git a/sys/amd64/amd64/support.S b/sys/amd64/amd64/support.S
index 09d4ef85b087..1d7d05843ba8 100644
--- a/sys/amd64/amd64/support.S
+++ b/sys/amd64/amd64/support.S
@@ -1566,20 +1566,19 @@ msr_onfault:
ret
ENTRY(wrmsr_early_safe)
+ movq %rsp,%r11
movl %edi,%ecx
movl %esi,%eax
sarq $32,%rsi
movl %esi,%edx
wrmsr
xorl %eax,%eax
-wrmsr_early_faulted:
ret
ENTRY(wrmsr_early_safe_gp_handler)
- addq $8,%rsp
+ movq %r11,%rsp
movl $EFAULT,%eax
- movq $wrmsr_early_faulted,(%rsp)
- iretq
+ ret
/*
* void pmap_pti_pcid_invalidate(uint64_t ucr3, uint64_t kcr3);