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Diffstat (limited to 'arch/arm64/kvm/hyp/sysreg-sr.c')
-rw-r--r--arch/arm64/kvm/hyp/sysreg-sr.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 76d016b446b2..68d6f7c3b237 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -152,8 +152,25 @@ static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
static void __hyp_text
__sysreg_restore_el2_return_state(struct kvm_cpu_context *ctxt)
{
+ u64 pstate = ctxt->gp_regs.regs.pstate;
+ u64 mode = pstate & PSR_AA32_MODE_MASK;
+
+ /*
+ * Safety check to ensure we're setting the CPU up to enter the guest
+ * in a less privileged mode.
+ *
+ * If we are attempting a return to EL2 or higher in AArch64 state,
+ * program SPSR_EL2 with M=EL2h and the IL bit set which ensures that
+ * we'll take an illegal exception state exception immediately after
+ * the ERET to the guest. Attempts to return to AArch32 Hyp will
+ * result in an illegal exception return because EL2's execution state
+ * is determined by SCR_EL3.RW.
+ */
+ if (!(mode & PSR_MODE32_BIT) && mode >= PSR_MODE_EL2t)
+ pstate = PSR_MODE_EL2h | PSR_IL_BIT;
+
write_sysreg_el2(ctxt->gp_regs.regs.pc, elr);
- write_sysreg_el2(ctxt->gp_regs.regs.pstate, spsr);
+ write_sysreg_el2(pstate, spsr);
if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
write_sysreg_s(ctxt->sys_regs[DISR_EL1], SYS_VDISR_EL2);