FEP is now the only reason for the #UD handler to run.
Signed-off-by: Alejandro Vallejo <[email protected]>
---
xen/arch/x86/hvm/hvm.c | 43 +++++++++++++++++++++---------------------
1 file changed, 21 insertions(+), 22 deletions(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index c8cae41705d..4c00cf4c4fe 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3837,35 +3837,34 @@ void hvm_ud_intercept(struct cpu_user_regs *regs)
struct vcpu *cur = current;
bool should_emulate = false;
struct hvm_emulate_ctxt ctxt;
+ const struct segment_register *cs;
+ uint32_t walk;
+ unsigned long addr;
+ char sig[5]; /* ud2; .ascii "xen" */
hvm_emulate_init_once(&ctxt, NULL, regs);
- if ( opt_hvm_fep )
+ cs = &ctxt.seg_reg[x86_seg_cs];
+ walk = ((ctxt.seg_reg[x86_seg_ss].dpl == 3)
+ ? PFEC_user_mode : 0) | PFEC_insn_fetch;
+
+ if ( hvm_virtual_to_linear_addr(x86_seg_cs, cs, regs->rip,
+ sizeof(sig), hvm_access_insn_fetch,
+ cs, &addr) &&
+ (hvm_copy_from_guest_linear(sig, addr, sizeof(sig),
+ walk, NULL) == HVMTRANS_okay) &&
+ (memcmp(sig, "\xf\xb" "xen", sizeof(sig)) == 0) )
{
- const struct segment_register *cs = &ctxt.seg_reg[x86_seg_cs];
- uint32_t walk = ((ctxt.seg_reg[x86_seg_ss].dpl == 3)
- ? PFEC_user_mode : 0) | PFEC_insn_fetch;
- unsigned long addr;
- char sig[5]; /* ud2; .ascii "xen" */
-
- if ( hvm_virtual_to_linear_addr(x86_seg_cs, cs, regs->rip,
- sizeof(sig), hvm_access_insn_fetch,
- cs, &addr) &&
- (hvm_copy_from_guest_linear(sig, addr, sizeof(sig),
- walk, NULL) == HVMTRANS_okay) &&
- (memcmp(sig, "\xf\xb" "xen", sizeof(sig)) == 0) )
- {
- regs->rip += sizeof(sig);
- regs->eflags &= ~X86_EFLAGS_RF;
+ regs->rip += sizeof(sig);
+ regs->eflags &= ~X86_EFLAGS_RF;
- /* Zero the upper 32 bits of %rip if not in 64bit mode. */
- if ( !(hvm_long_mode_active(cur) && cs->l) )
- regs->rip = (uint32_t)regs->rip;
+ /* Zero the upper 32 bits of %rip if not in 64bit mode. */
+ if ( !(hvm_long_mode_active(cur) && cs->l) )
+ regs->rip = (uint32_t)regs->rip;
- add_taint(TAINT_HVM_FEP);
+ add_taint(TAINT_HVM_FEP);
- should_emulate = true;
- }
+ should_emulate = true;
}
if ( !should_emulate )
--
2.43.0