From: "Pierre-Clément Tosi" <ptosi@google.com> To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Cc: Marc Zyngier <maz@kernel.org>, Oliver Upton <oliver.upton@linux.dev>, Suzuki K Poulose <suzuki.poulose@arm.com>, Vincent Donnefort <vdonnefort@google.com> Subject: [PATCH v2 04/12] KVM: arm64: nVHE: Simplify __guest_exit_panic path Date: Wed, 10 Apr 2024 09:28:39 +0100 [thread overview] Message-ID: <qw5au6bikvkeutkwbsbzlyrlue3yt44si7a2ehzzoliramekjg@ijifwx4fhomq> (raw) Immediately jump to __guest_exit_panic when taking an invalid EL2 exception with the nVHE host vector table instead of first duplicating the vCPU context check that __guest_exit_panic will also perform. Fix the wrong (probably bitrotten) __guest_exit_panic ABI doc to reflect how it is used by VHE and (now) nVHE and rename the routine to __hyp_panic to better reflect that it might not exit through the guest but will always (directly or indirectly) end up executing hyp_panic(). Use CPU_LR_OFFSET to clarify that the routine returns to hyp_panic(). Signed-off-by: Pierre-Clément Tosi <ptosi@google.com> --- arch/arm64/kvm/hyp/entry.S | 14 +++++++++----- arch/arm64/kvm/hyp/hyp-entry.S | 2 +- arch/arm64/kvm/hyp/include/hyp/switch.h | 4 ++-- arch/arm64/kvm/hyp/nvhe/host.S | 8 +------- 4 files changed, 13 insertions(+), 15 deletions(-) diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index bcaaf1a11b4e..6a1ce9d21e5b 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -83,7 +83,7 @@ alternative_else_nop_endif eret sb -SYM_INNER_LABEL(__guest_exit_restore_elr_and_panic, SYM_L_GLOBAL) +SYM_INNER_LABEL(__hyp_restore_elr_and_panic, SYM_L_GLOBAL) // x0-x29,lr: hyp regs stp x0, x1, [sp, #-16]! @@ -92,13 +92,15 @@ SYM_INNER_LABEL(__guest_exit_restore_elr_and_panic, SYM_L_GLOBAL) msr elr_el2, x0 ldp x0, x1, [sp], #16 -SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL) - // x2-x29,lr: vcpu regs - // vcpu x0-x1 on the stack +SYM_INNER_LABEL(__hyp_panic, SYM_L_GLOBAL) + // x0-x29,lr: vcpu regs + + stp x0, x1, [sp, #-16]! // If the hyp context is loaded, go straight to hyp_panic get_loaded_vcpu x0, x1 cbnz x0, 1f + ldp x0, x1, [sp], #16 b hyp_panic 1: @@ -110,10 +112,12 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL) // accurate if the guest had been completely restored. adr_this_cpu x0, kvm_hyp_ctxt, x1 adr_l x1, hyp_panic - str x1, [x0, #CPU_XREG_OFFSET(30)] + str x1, [x0, #CPU_LR_OFFSET] get_vcpu_ptr x1, x0 + // Keep x0-x1 on the stack for __guest_exit + SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL) // x0: return code // x1: vcpu diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index 03f97d71984c..7e65ef738ec9 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -122,7 +122,7 @@ el2_error: eret sb -.macro invalid_vector label, target = __guest_exit_panic +.macro invalid_vector label, target = __hyp_panic .align 2 SYM_CODE_START_LOCAL(\label) b \target diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 19a7ca2c1277..9387e3a0b680 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -753,7 +753,7 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) static inline void __kvm_unexpected_el2_exception(void) { - extern char __guest_exit_restore_elr_and_panic[]; + extern char __hyp_restore_elr_and_panic[]; unsigned long addr, fixup; struct kvm_exception_table_entry *entry, *end; unsigned long elr_el2 = read_sysreg(elr_el2); @@ -776,7 +776,7 @@ static inline void __kvm_unexpected_el2_exception(void) /* Trigger a panic after restoring the hyp context. */ this_cpu_ptr(&kvm_hyp_ctxt)->sys_regs[ELR_EL2] = elr_el2; - write_sysreg(__guest_exit_restore_elr_and_panic, elr_el2); + write_sysreg(__hyp_restore_elr_and_panic, elr_el2); } #endif /* __ARM64_KVM_HYP_SWITCH_H__ */ diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index 135cfb294ee5..7397b4f1838a 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -196,19 +196,13 @@ SYM_FUNC_END(__host_hvc) tbz x0, #PAGE_SHIFT, .L__hyp_sp_overflow\@ sub x0, sp, x0 // x0'' = sp' - x0' = (sp + x0) - sp = x0 sub sp, sp, x0 // sp'' = sp' - x0 = (sp + x0) - x0 = sp - /* If a guest is loaded, panic out of it. */ - stp x0, x1, [sp, #-16]! - get_loaded_vcpu x0, x1 - cbnz x0, __guest_exit_panic - add sp, sp, #16 - /* * The panic may not be clean if the exception is taken before the host * context has been saved by __host_exit or after the hyp context has * been partially clobbered by __host_enter. */ - b hyp_panic + b __hyp_panic .L__hyp_sp_overflow\@: /* Switch to the overflow stack */ -- 2.44.0.478.gd926399ef9-goog -- Pierre
WARNING: multiple messages have this Message-ID (diff)
From: "Pierre-Clément Tosi" <ptosi@google.com> To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Cc: Marc Zyngier <maz@kernel.org>, Oliver Upton <oliver.upton@linux.dev>, Suzuki K Poulose <suzuki.poulose@arm.com>, Vincent Donnefort <vdonnefort@google.com> Subject: [PATCH v2 04/12] KVM: arm64: nVHE: Simplify __guest_exit_panic path Date: Wed, 10 Apr 2024 09:28:39 +0100 [thread overview] Message-ID: <qw5au6bikvkeutkwbsbzlyrlue3yt44si7a2ehzzoliramekjg@ijifwx4fhomq> (raw) Immediately jump to __guest_exit_panic when taking an invalid EL2 exception with the nVHE host vector table instead of first duplicating the vCPU context check that __guest_exit_panic will also perform. Fix the wrong (probably bitrotten) __guest_exit_panic ABI doc to reflect how it is used by VHE and (now) nVHE and rename the routine to __hyp_panic to better reflect that it might not exit through the guest but will always (directly or indirectly) end up executing hyp_panic(). Use CPU_LR_OFFSET to clarify that the routine returns to hyp_panic(). Signed-off-by: Pierre-Clément Tosi <ptosi@google.com> --- arch/arm64/kvm/hyp/entry.S | 14 +++++++++----- arch/arm64/kvm/hyp/hyp-entry.S | 2 +- arch/arm64/kvm/hyp/include/hyp/switch.h | 4 ++-- arch/arm64/kvm/hyp/nvhe/host.S | 8 +------- 4 files changed, 13 insertions(+), 15 deletions(-) diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index bcaaf1a11b4e..6a1ce9d21e5b 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -83,7 +83,7 @@ alternative_else_nop_endif eret sb -SYM_INNER_LABEL(__guest_exit_restore_elr_and_panic, SYM_L_GLOBAL) +SYM_INNER_LABEL(__hyp_restore_elr_and_panic, SYM_L_GLOBAL) // x0-x29,lr: hyp regs stp x0, x1, [sp, #-16]! @@ -92,13 +92,15 @@ SYM_INNER_LABEL(__guest_exit_restore_elr_and_panic, SYM_L_GLOBAL) msr elr_el2, x0 ldp x0, x1, [sp], #16 -SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL) - // x2-x29,lr: vcpu regs - // vcpu x0-x1 on the stack +SYM_INNER_LABEL(__hyp_panic, SYM_L_GLOBAL) + // x0-x29,lr: vcpu regs + + stp x0, x1, [sp, #-16]! // If the hyp context is loaded, go straight to hyp_panic get_loaded_vcpu x0, x1 cbnz x0, 1f + ldp x0, x1, [sp], #16 b hyp_panic 1: @@ -110,10 +112,12 @@ SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL) // accurate if the guest had been completely restored. adr_this_cpu x0, kvm_hyp_ctxt, x1 adr_l x1, hyp_panic - str x1, [x0, #CPU_XREG_OFFSET(30)] + str x1, [x0, #CPU_LR_OFFSET] get_vcpu_ptr x1, x0 + // Keep x0-x1 on the stack for __guest_exit + SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL) // x0: return code // x1: vcpu diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index 03f97d71984c..7e65ef738ec9 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -122,7 +122,7 @@ el2_error: eret sb -.macro invalid_vector label, target = __guest_exit_panic +.macro invalid_vector label, target = __hyp_panic .align 2 SYM_CODE_START_LOCAL(\label) b \target diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 19a7ca2c1277..9387e3a0b680 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -753,7 +753,7 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) static inline void __kvm_unexpected_el2_exception(void) { - extern char __guest_exit_restore_elr_and_panic[]; + extern char __hyp_restore_elr_and_panic[]; unsigned long addr, fixup; struct kvm_exception_table_entry *entry, *end; unsigned long elr_el2 = read_sysreg(elr_el2); @@ -776,7 +776,7 @@ static inline void __kvm_unexpected_el2_exception(void) /* Trigger a panic after restoring the hyp context. */ this_cpu_ptr(&kvm_hyp_ctxt)->sys_regs[ELR_EL2] = elr_el2; - write_sysreg(__guest_exit_restore_elr_and_panic, elr_el2); + write_sysreg(__hyp_restore_elr_and_panic, elr_el2); } #endif /* __ARM64_KVM_HYP_SWITCH_H__ */ diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index 135cfb294ee5..7397b4f1838a 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -196,19 +196,13 @@ SYM_FUNC_END(__host_hvc) tbz x0, #PAGE_SHIFT, .L__hyp_sp_overflow\@ sub x0, sp, x0 // x0'' = sp' - x0' = (sp + x0) - sp = x0 sub sp, sp, x0 // sp'' = sp' - x0 = (sp + x0) - x0 = sp - /* If a guest is loaded, panic out of it. */ - stp x0, x1, [sp, #-16]! - get_loaded_vcpu x0, x1 - cbnz x0, __guest_exit_panic - add sp, sp, #16 - /* * The panic may not be clean if the exception is taken before the host * context has been saved by __host_exit or after the hyp context has * been partially clobbered by __host_enter. */ - b hyp_panic + b __hyp_panic .L__hyp_sp_overflow\@: /* Switch to the overflow stack */ -- 2.44.0.478.gd926399ef9-goog -- Pierre _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2024-04-10 8:28 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-04-10 8:28 Pierre-Clément Tosi [this message] 2024-04-10 8:28 ` [PATCH v2 04/12] KVM: arm64: nVHE: Simplify __guest_exit_panic path Pierre-Clément Tosi
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