The fault decoding process (including computing the IPA in the case of a permission fault) would be much better done in C code, as we have a reasonable infrastructure to deal with the VHE/non-VHE differences. Let's move the whole thing to C, including the workaround for erratum 834220, and just patch the odd ESR_EL2 access remaining in hyp-entry.S. Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> --- arch/arm64/kernel/asm-offsets.c | 3 -- arch/arm64/kvm/hyp/hyp-entry.S | 69 +++-------------------------------------- arch/arm64/kvm/hyp/switch.c | 54 ++++++++++++++++++++++++++++++++ 3 files changed, 59 insertions(+), 67 deletions(-) diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index fffa4ac6..b0ab4e9 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -110,9 +110,6 @@ int main(void) DEFINE(CPU_USER_PT_REGS, offsetof(struct kvm_regs, regs)); DEFINE(CPU_FP_REGS, offsetof(struct kvm_regs, fp_regs)); DEFINE(VCPU_FPEXC32_EL2, offsetof(struct kvm_vcpu, arch.ctxt.sys_regs[FPEXC32_EL2])); - DEFINE(VCPU_ESR_EL2, offsetof(struct kvm_vcpu, arch.fault.esr_el2)); - DEFINE(VCPU_FAR_EL2, offsetof(struct kvm_vcpu, arch.fault.far_el2)); - DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2)); DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context)); #endif #ifdef CONFIG_CPU_PM diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index 9e0683f..213de52 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -19,7 +19,6 @@ #include <asm/alternative.h> #include <asm/assembler.h> -#include <asm/asm-offsets.h> #include <asm/cpufeature.h> #include <asm/kvm_arm.h> #include <asm/kvm_asm.h> @@ -67,7 +66,11 @@ ENDPROC(__vhe_hyp_call) el1_sync: // Guest trapped into EL2 save_x0_to_x3 +alternative_if_not ARM64_HAS_VIRT_HOST_EXTN mrs x1, esr_el2 +alternative_else + mrs x1, esr_el1 +alternative_endif lsr x2, x1, #ESR_ELx_EC_SHIFT cmp x2, #ESR_ELx_EC_HVC64 @@ -103,72 +106,10 @@ el1_trap: cmp x2, #ESR_ELx_EC_FP_ASIMD b.eq __fpsimd_guest_restore - cmp x2, #ESR_ELx_EC_DABT_LOW - mov x0, #ESR_ELx_EC_IABT_LOW - ccmp x2, x0, #4, ne - b.ne 1f // Not an abort we care about - - /* This is an abort. Check for permission fault */ -alternative_if_not ARM64_WORKAROUND_834220 - and x2, x1, #ESR_ELx_FSC_TYPE - cmp x2, #FSC_PERM - b.ne 1f // Not a permission fault -alternative_else - nop // Use the permission fault path to - nop // check for a valid S1 translation, - nop // regardless of the ESR value. -alternative_endif - - /* - * Check for Stage-1 page table walk, which is guaranteed - * to give a valid HPFAR_EL2. - */ - tbnz x1, #7, 1f // S1PTW is set - - /* Preserve PAR_EL1 */ - mrs x3, par_el1 - stp x3, xzr, [sp, #-16]! - - /* - * Permission fault, HPFAR_EL2 is invalid. - * Resolve the IPA the hard way using the guest VA. - * Stage-1 translation already validated the memory access rights. - * As such, we can use the EL1 translation regime, and don't have - * to distinguish between EL0 and EL1 access. - */ - mrs x2, far_el2 - at s1e1r, x2 - isb - - /* Read result */ - mrs x3, par_el1 - ldp x0, xzr, [sp], #16 // Restore PAR_EL1 from the stack - msr par_el1, x0 - tbnz x3, #0, 3f // Bail out if we failed the translation - ubfx x3, x3, #12, #36 // Extract IPA - lsl x3, x3, #4 // and present it like HPFAR - b 2f - -1: mrs x3, hpfar_el2 - mrs x2, far_el2 - -2: mrs x0, tpidr_el2 - str w1, [x0, #VCPU_ESR_EL2] - str x2, [x0, #VCPU_FAR_EL2] - str x3, [x0, #VCPU_HPFAR_EL2] - + mrs x0, tpidr_el2 mov x1, #ARM_EXCEPTION_TRAP b __guest_exit - /* - * Translation failed. Just return to the guest and - * let it fault again. Another CPU is probably playing - * behind our back. - */ -3: restore_x0_to_x3 - - eret - el1_irq: save_x0_to_x3 mrs x0, tpidr_el2 diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 0cadb7f..df2cce9 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -15,6 +15,7 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/types.h> #include <asm/kvm_asm.h> #include "hyp.h" @@ -150,6 +151,55 @@ static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu) __vgic_call_restore_state()(vcpu); } +static hyp_alternate_value(__check_arm_834220, + false, true, + ARM64_WORKAROUND_834220); + +static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu) +{ + u64 esr = read_sysreg_el2(esr); + u8 ec = esr >> ESR_ELx_EC_SHIFT; + u64 hpfar, far; + + vcpu->arch.fault.esr_el2 = esr; + + if (ec != ESR_ELx_EC_DABT_LOW && ec != ESR_ELx_EC_IABT_LOW) + return true; + + far = read_sysreg_el2(far); + + if (!(esr & ESR_ELx_S1PTW) && + (__check_arm_834220() || (esr & ESR_ELx_FSC_TYPE) == FSC_PERM)) { + u64 par, tmp; + + /* + * Permission fault, HPFAR_EL2 is invalid. Resolve the + * IPA the hard way using the guest VA. + * Stage-1 translation already validated the memory + * access rights. As such, we can use the EL1 + * translation regime, and don't have to distinguish + * between EL0 and EL1 access. + */ + par = read_sysreg(par_el1); + asm volatile("at s1e1r, %0" : : "r" (far)); + isb(); + + tmp = read_sysreg(par_el1); + write_sysreg(par, par_el1); + + if (unlikely(tmp & 1)) + return false; /* Translation failed, back to guest */ + + hpfar = ((tmp >> 12) & ((1UL << 36) - 1)) << 4; + } else { + hpfar = read_sysreg(hpfar_el2); + } + + vcpu->arch.fault.far_el2 = far; + vcpu->arch.fault.hpfar_el2 = hpfar; + return true; +} + static int __hyp_text __guest_run(struct kvm_vcpu *vcpu) { struct kvm_cpu_context *host_ctxt; @@ -181,9 +231,13 @@ static int __hyp_text __guest_run(struct kvm_vcpu *vcpu) __debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt); /* Jump in the fire! */ +again: exit_code = __guest_enter(vcpu, host_ctxt); /* And we're baaack! */ + if (exit_code == ARM_EXCEPTION_TRAP && !__populate_fault_info(vcpu)) + goto again; + fp_enabled = __fpsimd_enabled(); __sysreg_save_guest_state(guest_ctxt); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
