From 4c47eb1c18c38b755eb4894a6ca38f834de3ec23 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 19 Jul 2016 13:56:54 +0100 Subject: [PATCH] arm64: KVM: VHE: Context switch MDSCR_EL1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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@vger.kernel.org #4.6 Reported-by: Tirumalesh Chalamarla Tested-by: Tirumalesh Chalamarla Signed-off-by: Marc Zyngier Signed-off-by: Radim Krčmář --- 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 0f7c40eb3f53..934137647837 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); -- 2.20.1