From: Jintack Lim <[email protected]> Forward traps due to FP/ASIMD register accesses to the virtual EL2 if virtual CPTR_EL2.TFP is set (with HCR_EL2.E2H == 0) or CPTR_EL2.FPEN is configure to do so (with HCR_EL2.E2h == 1).
Signed-off-by: Jintack Lim <[email protected]> Signed-off-by: Christoffer Dall <[email protected]> [maz: account for HCR_EL2.E2H when testing for TFP/FPEN, with all the hard work actually being done by Chase Conklin] Signed-off-by: Marc Zyngier <[email protected]> --- arch/arm64/include/asm/kvm_emulate.h | 26 +++++++++++++++++++++++++ arch/arm64/kvm/handle_exit.c | 16 +++++++++++---- arch/arm64/kvm/hyp/include/hyp/switch.h | 8 ++++++-- 3 files changed, 44 insertions(+), 6 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index f63872db1e39..12935f6a7aa9 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -11,12 +11,14 @@ #ifndef __ARM64_KVM_EMULATE_H__ #define __ARM64_KVM_EMULATE_H__ +#include <linux/bitfield.h> #include <linux/kvm_host.h> #include <asm/debug-monitors.h> #include <asm/esr.h> #include <asm/kvm_arm.h> #include <asm/kvm_hyp.h> +#include <asm/kvm_nested.h> #include <asm/ptrace.h> #include <asm/cputype.h> #include <asm/virt.h> @@ -321,6 +323,30 @@ static inline bool vcpu_mode_priv(const struct kvm_vcpu *vcpu) return mode != PSR_MODE_EL0t; } +static inline bool guest_hyp_fpsimd_traps_enabled(const struct kvm_vcpu *vcpu) +{ + u64 val; + + if (!nested_virt_in_use(vcpu)) + return false; + + val = vcpu_read_sys_reg(vcpu, CPTR_EL2); + + if (!vcpu_el2_e2h_is_set(vcpu)) + return (val & CPTR_EL2_TFP); + + switch (FIELD_GET(CPACR_EL1_FPEN, val)) { + case 0b00: + case 0b10: + return true; + case 0b01: + return vcpu_el2_tge_is_set(vcpu) && !vcpu_mode_el2(vcpu); + case 0b11: + default: /* GCC is dumb */ + return false; + } +} + static __always_inline u32 kvm_vcpu_get_esr(const struct kvm_vcpu *vcpu) { return vcpu->arch.fault.esr_el2; diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 2f579152df0b..3380c5a91b60 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -96,11 +96,19 @@ static int handle_smc(struct kvm_vcpu *vcpu) } /* - * Guest access to FP/ASIMD registers are routed to this handler only - * when the system doesn't support FP/ASIMD. + * This handles the cases where the system does not support FP/ASIMD or when + * we are running nested virtualization and the guest hypervisor is trapping + * FP/ASIMD accesses by its guest guest. + * + * All other handling of guest vs. host FP/ASIMD register state is handled in + * fixup_guest_exit(). */ -static int handle_no_fpsimd(struct kvm_vcpu *vcpu) +static int kvm_handle_fpasimd(struct kvm_vcpu *vcpu) { + if (guest_hyp_fpsimd_traps_enabled(vcpu)) + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + + /* This is the case when the system doesn't support FP/ASIMD. */ kvm_inject_undefined(vcpu); return 1; } @@ -243,7 +251,7 @@ static exit_handle_fn arm_exit_handlers[] = { [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug, [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug, [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug, - [ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd, + [ESR_ELx_EC_FP_ASIMD] = kvm_handle_fpasimd, [ESR_ELx_EC_PAC] = kvm_handle_ptrauth, }; diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index bd2a7a6ae5d7..0790eb2b7545 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -242,8 +242,12 @@ static inline bool __hyp_handle_fpsimd(struct kvm_vcpu *vcpu) esr_ec != ESR_ELx_EC_SVE) return false; - /* Don't handle SVE traps for non-SVE vcpus here: */ - if (!sve_guest && esr_ec != ESR_ELx_EC_FP_ASIMD) + /* + * Don't handle SVE traps for non-SVE vcpus here. This + * includes NV guests for the time being. + */ + if (!sve_guest && (esr_ec != ESR_ELx_EC_FP_ASIMD || + guest_hyp_fpsimd_traps_enabled(vcpu))) return false; /* Valid trap. Switch the context: */ -- 2.29.2 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
