>From 3dcb529de23adb918b9a4d6eca717c737f380bc3 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Fri, 15 Jan 2016 13:18:06 -0500 Subject: [PATCH] gic: update save/restore pointers only when gic v3 detected The original code set up the VGIC save/restore calls in __kvm_vcpu_run() based on whether the GIC had been detected as v2 or v3. Commit 8a14849b4a35 ("arm64: KVM: Switch vgic save/restore to alternative_insn") switched to making that choice based on whether the processor feature register reports that the system register interface to the GIC CPU interface is supported. However, booting up with the GIC v3 in v2 compatibility mode (in this case on the Linaro Foundation Model simulator) we find that the v3 save/restore isn't the right thing, since we end up with no timer interrupts being delivered to the KVM guest. Reverting to a model where we set up the VGIC save/restore calls based on the actual GIC type fixes this. To do this and still keep the simplicity of the "alternatives" model, we instead leave the v2 branch-and-link instruction in place, but patch it dynamically to be a branch-and-link to the v3 routines if we detect a v3 GIC. Signed-off-by: Chris Metcalf --- arch/arm/include/asm/kvm_host.h | 5 +++++ arch/arm64/include/asm/kvm_host.h | 37 +++++++++++++++++++++++++++++++++++++ arch/arm64/kvm/hyp.S | 14 ++++---------- virt/kvm/arm/vgic.c | 3 +++ 4 files changed, 49 insertions(+), 10 deletions(-) diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index c4072d9f32c7..a34ce4d73498 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -216,6 +216,11 @@ static inline int kvm_arch_dev_ioctl_check_extension(long ext) return 0; } +static inline void vgic_arch_setup(const struct vgic_params *vgic) +{ + BUG_ON(vgic->type != VGIC_V2); +} + int kvm_perf_init(void); int kvm_perf_teardown(void); diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index ed039688c221..9ce98e69b5ec 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -27,6 +27,7 @@ #include #include #include +#include #define __KVM_HAVE_ARCH_INTC_INITIALIZED @@ -244,6 +245,42 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr, hyp_stack_ptr, vector_ptr); } +#ifdef CONFIG_ARM_GIC_V3 +/* Write a 'bl FUNC' instruction at address CALLSITE. */ +static inline void vgic_patch(char *callsite, char *func) +{ + aarch64_insn_patch_text_nosync( + callsite, + aarch64_insn_gen_branch_imm((long)callsite, (long)func, + AARCH64_INSN_BRANCH_LINK)); +} +#endif + +static inline void vgic_arch_setup(const struct vgic_params *vgic) +{ + switch(vgic->type) + { + case VGIC_V2: + break; + +#ifdef CONFIG_ARM_GIC_V3 + case VGIC_V3: + { + extern char __save_vgic_state_insn[]; + extern char __save_vgic_v3_state[]; + extern char __restore_vgic_state_insn[]; + extern char __restore_vgic_v3_state[]; + vgic_patch(__save_vgic_state_insn, __save_vgic_v3_state); + vgic_patch(__restore_vgic_state_insn, __restore_vgic_v3_state); + break; + } +#endif + + default: + BUG(); + } +} + static inline void kvm_arch_hardware_disable(void) {} static inline void kvm_arch_hardware_unsetup(void) {} static inline void kvm_arch_sync_events(struct kvm *kvm) {} diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index e5836138ec42..6b1eded53051 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -518,11 +518,8 @@ * Call into the vgic backend for state saving */ .macro save_vgic_state -alternative_if_not ARM64_HAS_SYSREG_GIC_CPUIF - bl __save_vgic_v2_state -alternative_else - bl __save_vgic_v3_state -alternative_endif +ENTRY(__save_vgic_state_insn) + bl __save_vgic_v2_state // may update to __save_vgic_v3_state mrs x24, hcr_el2 mov x25, #HCR_INT_OVERRIDE neg x25, x25 @@ -539,11 +536,8 @@ alternative_endif orr x24, x24, #HCR_INT_OVERRIDE orr x24, x24, x25 msr hcr_el2, x24 -alternative_if_not ARM64_HAS_SYSREG_GIC_CPUIF - bl __restore_vgic_v2_state -alternative_else - bl __restore_vgic_v3_state -alternative_endif +ENTRY(__restore_vgic_state_insn) + bl __restore_vgic_v2_state // may update to __restore_vgic_v3_state .endm .macro save_timer_state diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 66c66165e712..8b4215414d11 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -2502,6 +2502,9 @@ int kvm_vgic_hyp_init(void) goto out_free_irq; } + /* Callback into for arch code for setup */ + vgic_arch_setup(vgic); + on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1); return 0; -- 2.1.2