From bea608299d28ee4e10db3468985dde440adb09b7 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 21 Jul 2026 18:07:53 +0100 Subject: KVM: arm64: vgic-v3: Simplify initial GICv3 configuration sampling Now that we have our magic inline helper for ICH_VTR_EL2, we can get rid of the hack that was reporting a combination of that register and of the indication of the CPU interface supporting GICv2 compatibility. We now only report the latter. As a small benefit, GICv5 is not involved in this stuff anymore, since it never has GICv2 compatibility.. Signed-off-by: Marc Zyngier Link: https://patch.msgid.link/20260721170754.3150521-6-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/include/asm/kvm_asm.h | 2 +- arch/arm64/kvm/hyp/vgic-v3-sr.c | 23 +++-------------------- arch/arm64/kvm/vgic/vgic-v3.c | 9 +++------ arch/arm64/kvm/vgic/vgic-v5.c | 2 +- 4 files changed, 8 insertions(+), 28 deletions(-) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 043495f7fc78..cb354a037fc5 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -281,7 +281,7 @@ extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu); extern void __kvm_adjust_pc(struct kvm_vcpu *vcpu); -extern u64 __vgic_v3_get_gic_config(void); +extern bool __vgic_v3_get_gic_config(void); extern void __vgic_v3_init_lrs(void); #define __KVM_EXTABLE(from, to) \ diff --git a/arch/arm64/kvm/hyp/vgic-v3-sr.c b/arch/arm64/kvm/hyp/vgic-v3-sr.c index 3e5d5ddf35a1..74d4a509f1de 100644 --- a/arch/arm64/kvm/hyp/vgic-v3-sr.c +++ b/arch/arm64/kvm/hyp/vgic-v3-sr.c @@ -437,26 +437,12 @@ void __vgic_v3_init_lrs(void) __gic_v3_set_lr(0, i); } -/* - * Return the GIC CPU configuration: - * - [31:0] ICH_VTR_EL2 - * - [62:32] RES0 - * - [63] MMIO (GICv2) capable - */ -u64 __vgic_v3_get_gic_config(void) +/* Return true if GICv3 is MMIO (GICv2) capable, false otherwise */ +bool __vgic_v3_get_gic_config(void) { u64 val, sre; unsigned long flags = 0; - /* - * In compat mode, we cannot access ICC_SRE_EL1 at any EL - * other than EL1 itself; just return the - * ICH_VTR_EL2. ICC_IDR0_EL1 is only implemented on a GICv5 - * system, so we first check if we have GICv5 support. - */ - if (cpus_have_final_cap(ARM64_HAS_GICV5_CPUIF)) - return vgic_ich_vtr(); - sre = read_gicreg(ICC_SRE_EL1); /* * To check whether we have a MMIO-based (GICv2 compatible) @@ -497,10 +483,7 @@ u64 __vgic_v3_get_gic_config(void) isb(); } - val = (val & ICC_SRE_EL1_SRE) ? 0 : (1ULL << 63); - val |= vgic_ich_vtr(); - - return val; + return !(val & ICC_SRE_EL1_SRE); } static void __vgic_v3_compat_mode_enable(void) diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c index 098187e34c58..734fa3138723 100644 --- a/arch/arm64/kvm/vgic/vgic-v3.c +++ b/arch/arm64/kvm/vgic/vgic-v3.c @@ -936,12 +936,12 @@ void vgic_v3_enable_cpuif_traps(void) */ int vgic_v3_probe(const struct gic_kvm_info *info) { - u64 ich_vtr_el2 = kvm_call_hyp_ret(__vgic_v3_get_gic_config); + u64 ich_vtr_el2; bool has_v2; int ret; - has_v2 = ich_vtr_el2 >> 63; - ich_vtr_el2 = (u32)ich_vtr_el2; + has_v2 = kvm_call_hyp_ret(__vgic_v3_get_gic_config); + ich_vtr_el2 = vgic_ich_vtr(); /* * The ListRegs field is 5 bits, but there is an architectural @@ -996,9 +996,6 @@ int vgic_v3_probe(const struct gic_kvm_info *info) if (has_v2) static_branch_enable(&vgic_v3_has_v2_compat); - if (vgic_v3_broken_seis()) - kvm_vgic_global_state.ich_vtr_el2 &= ~ICH_VTR_EL2_SEIS; - vgic_v3_enable_cpuif_traps(); kvm_vgic_global_state.vctrl_base = NULL; diff --git a/arch/arm64/kvm/vgic/vgic-v5.c b/arch/arm64/kvm/vgic/vgic-v5.c index d4789ff3e740..16bc0a670d3e 100644 --- a/arch/arm64/kvm/vgic/vgic-v5.c +++ b/arch/arm64/kvm/vgic/vgic-v5.c @@ -83,7 +83,7 @@ skip_v5: } kvm_vgic_global_state.has_gcie_v3_compat = true; - ich_vtr_el2 = kvm_call_hyp_ret(__vgic_v3_get_gic_config); + ich_vtr_el2 = vgic_ich_vtr(); kvm_vgic_global_state.ich_vtr_el2 = (u32)ich_vtr_el2; /* -- cgit v1.2.3