[PATCH v4 17/40] KVM: arm64: Move userspace system registers into separate function
From: Christoffer Dall <hidden>
Date: 2018-02-15 21:03:09
Also in:
kvm, kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
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.
ACTLR_EL1 is not used by a VHE host, so we can move this register into
the EL1 state which is not saved/restored 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 <redacted>
Signed-off-by: Christoffer Dall <redacted>
---
Notes:
Changes since v3:
- Correct the comment about ACTLR_EL1 and adjust commit text.
Changes since v2:
- Save restore ACTLR_EL1 as part of the EL1 registers state instead of
the user register state, as ACTLR_EL1 can't affect the host's execution
on VHE systems.
Changes since v1:
- Added comment about sp_el0 to common save sysreg save/restore functions
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