The kprobe enablement work has uncovered that changes made by
a guest to MDSCR_EL1 were propagated to the host when VHE was
enabled, leading to unexpected exception being delivered.
Moving this register to the list of registers that are always
context-switched fixes the issue.
Fixes: 9c6c35683286 ("arm64: KVM: VHE: Split save/restore of registers shared between guest and host")
Cc: stable@xxxxxxxxxxxxxxx #4.6
Reported-by: Tirumalesh Chalamarla <Tirumalesh.Chalamarla@xxxxxxxxxx>
Tested-by: Tirumalesh Chalamarla <Tirumalesh.Chalamarla@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
v2: added missing Fixes and Cc-stable tags
arch/arm64/kvm/hyp/sysreg-sr.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 0f7c40e..9341376 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -27,8 +27,8 @@ static void __hyp_text __sysreg_do_nothing(struct kvm_cpu_context *ctxt) { }
/*
* Non-VHE: Both host and guest must save everything.
*
- * VHE: Host must save tpidr*_el[01], actlr_el1, sp0, pc, pstate, and
- * guest must save everything.
+ * VHE: Host must save tpidr*_el[01], actlr_el1, mdscr_el1, sp0, pc,
+ * pstate, and guest must save everything.
*/
static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
@@ -37,6 +37,7 @@ static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
ctxt->sys_regs[TPIDR_EL0] = read_sysreg(tpidr_el0);
ctxt->sys_regs[TPIDRRO_EL0] = read_sysreg(tpidrro_el0);
ctxt->sys_regs[TPIDR_EL1] = read_sysreg(tpidr_el1);
+ ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
ctxt->gp_regs.regs.pc = read_sysreg_el2(elr);
ctxt->gp_regs.regs.pstate = read_sysreg_el2(spsr);
@@ -61,7 +62,6 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
ctxt->sys_regs[AMAIR_EL1] = read_sysreg_el1(amair);
ctxt->sys_regs[CNTKCTL_EL1] = read_sysreg_el1(cntkctl);
ctxt->sys_regs[PAR_EL1] = read_sysreg(par_el1);
- ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
ctxt->gp_regs.sp_el1 = read_sysreg(sp_el1);
ctxt->gp_regs.elr_el1 = read_sysreg_el1(elr);
@@ -90,6 +90,7 @@ static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctx
write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
write_sysreg(ctxt->sys_regs[TPIDR_EL1], tpidr_el1);
+ write_sysreg(ctxt->sys_regs[MDSCR_EL1], mdscr_el1);
write_sysreg(ctxt->gp_regs.regs.sp, sp_el0);
write_sysreg_el2(ctxt->gp_regs.regs.pc, elr);
write_sysreg_el2(ctxt->gp_regs.regs.pstate, spsr);
@@ -114,7 +115,6 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
write_sysreg_el1(ctxt->sys_regs[AMAIR_EL1], amair);
write_sysreg_el1(ctxt->sys_regs[CNTKCTL_EL1], cntkctl);
write_sysreg(ctxt->sys_regs[PAR_EL1], par_el1);
- write_sysreg(ctxt->sys_regs[MDSCR_EL1], mdscr_el1);
write_sysreg(ctxt->gp_regs.sp_el1, sp_el1);
write_sysreg_el1(ctxt->gp_regs.elr_el1, elr);
--
2.1.4
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