From: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
There's a semantic difference between the EL1 registers that control
operation of a kernel running in EL1 and EL1 registers that only control
userspace execution in EL0. Since we can defer saving/restoring the
latter, move them into their own function.
The ARMv8 ARM (ARM DDI 0487C.a) Section D10.2.1 recommends that
ACTLR_EL1 has no effect on the processor when running the VHE host, and
we can therefore move this register into the EL1 state which is only
saved/restored on vcpu_put/load for a VHE host.
We also take this chance to rename the function saving/restoring the
remaining system register to make it clear this function deals with
the EL1 system registers.
Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm64/kvm/hyp/sysreg-sr.c | 48 ++++++++++++++++++++++++++++++------------
1 file changed, 35 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 99fc60516103..d5a5145b4e7c 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -28,24 +28,33 @@ 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*_el0, actlr_el1, mdscr_el1, sp_el0,
+ * VHE: Host must save tpidr*_el0, mdscr_el1, sp_el0,
* and guest must save everything.
*/
static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
{
- ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
- ctxt->sys_regs[TPIDR_EL0] = read_sysreg(tpidr_el0);
- ctxt->sys_regs[TPIDRRO_EL0] = read_sysreg(tpidrro_el0);
ctxt->sys_regs[MDSCR_EL1] = read_sysreg(mdscr_el1);
+
+ /*
+ * The host arm64 Linux uses sp_el0 to point to 'current' and it must
+ * therefore be saved/restored on every entry/exit to/from the guest.
+ */
ctxt->gp_regs.regs.sp = read_sysreg(sp_el0);
}
-static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
+static void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
+{
+ ctxt->sys_regs[TPIDR_EL0] = read_sysreg(tpidr_el0);
+ ctxt->sys_regs[TPIDRRO_EL0] = read_sysreg(tpidrro_el0);
+}
+
+static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
{
ctxt->sys_regs[MPIDR_EL1] = read_sysreg(vmpidr_el2);
ctxt->sys_regs[CSSELR_EL1] = read_sysreg(csselr_el1);
ctxt->sys_regs[SCTLR_EL1] = read_sysreg_el1(sctlr);
+ ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1);
ctxt->sys_regs[CPACR_EL1] = read_sysreg_el1(cpacr);
ctxt->sys_regs[TTBR0_EL1] = read_sysreg_el1(ttbr0);
ctxt->sys_regs[TTBR1_EL1] = read_sysreg_el1(ttbr1);
@@ -73,35 +82,46 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
}
static hyp_alternate_select(__sysreg_call_save_host_state,
- __sysreg_save_state, __sysreg_do_nothing,
+ __sysreg_save_el1_state, __sysreg_do_nothing,
ARM64_HAS_VIRT_HOST_EXTN);
void __hyp_text __sysreg_save_host_state(struct kvm_cpu_context *ctxt)
{
__sysreg_call_save_host_state()(ctxt);
__sysreg_save_common_state(ctxt);
+ __sysreg_save_user_state(ctxt);
}
void __hyp_text __sysreg_save_guest_state(struct kvm_cpu_context *ctxt)
{
- __sysreg_save_state(ctxt);
+ __sysreg_save_el1_state(ctxt);
__sysreg_save_common_state(ctxt);
+ __sysreg_save_user_state(ctxt);
}
static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
{
- write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
- write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
- write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
write_sysreg(ctxt->sys_regs[MDSCR_EL1], mdscr_el1);
+
+ /*
+ * The host arm64 Linux uses sp_el0 to point to 'current' and it must
+ * therefore be saved/restored on every entry/exit to/from the guest.
+ */
write_sysreg(ctxt->gp_regs.regs.sp, sp_el0);
}
-static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
+static void __hyp_text __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
+{
+ write_sysreg(ctxt->sys_regs[TPIDR_EL0], tpidr_el0);
+ write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);
+}
+
+static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
{
write_sysreg(ctxt->sys_regs[MPIDR_EL1], vmpidr_el2);
write_sysreg(ctxt->sys_regs[CSSELR_EL1], csselr_el1);
write_sysreg_el1(ctxt->sys_regs[SCTLR_EL1], sctlr);
+ write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1);
write_sysreg_el1(ctxt->sys_regs[CPACR_EL1], cpacr);
write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1], ttbr0);
write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1], ttbr1);
@@ -129,19 +149,21 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
}
static hyp_alternate_select(__sysreg_call_restore_host_state,
- __sysreg_restore_state, __sysreg_do_nothing,
+ __sysreg_restore_el1_state, __sysreg_do_nothing,
ARM64_HAS_VIRT_HOST_EXTN);
void __hyp_text __sysreg_restore_host_state(struct kvm_cpu_context *ctxt)
{
__sysreg_call_restore_host_state()(ctxt);
__sysreg_restore_common_state(ctxt);
+ __sysreg_restore_user_state(ctxt);
}
void __hyp_text __sysreg_restore_guest_state(struct kvm_cpu_context *ctxt)
{
- __sysreg_restore_state(ctxt);
+ __sysreg_restore_el1_state(ctxt);
__sysreg_restore_common_state(ctxt);
+ __sysreg_restore_user_state(ctxt);
}
void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
--
2.14.2
