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Message-ID: <87h98gs853.fsf@e105922-lin.cambridge.arm.com>
Date: Thu, 13 Oct 2016 14:14:48 +0100
From: Punit Agrawal <punit.agrawal@....com>
To: Tyler Baicar <tbaicar@...eaurora.org>
Cc: christoffer.dall@...aro.org, marc.zyngier@....com,
pbonzini@...hat.com, rkrcmar@...hat.com, linux@...linux.org.uk,
catalin.marinas@....com, will.deacon@....com, rjw@...ysocki.net,
lenb@...nel.org, matt@...eblueprint.co.uk, robert.moore@...el.com,
lv.zheng@...el.com, mark.rutland@....com, james.morse@....com,
akpm@...ux-foundation.org, sandeepa.s.prabhu@...il.com,
shijie.huang@....com, paul.gortmaker@...driver.com,
tomasz.nowicki@...aro.org, fu.wei@...aro.org, rostedt@...dmis.org,
bristot@...hat.com, linux-arm-kernel@...ts.infradead.org,
kvmarm@...ts.cs.columbia.edu, Dkvm@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
linux-efi@...r.kernel.org, devel@...ica.org
Subject: Re: [PATCH V3 10/10] arm64: KVM: add guest SEA support
Hi Tyler,
I know I've had my last comment already ;), but I thought I'd rather
raise the question than stay confused...
Tyler Baicar <tbaicar@...eaurora.org> writes:
> Currently external aborts are unsupported by the guest abort
> handling. Add handling for SEAs so that the host kernel reports
> SEAs which occur in the guest kernel.
>
> Signed-off-by: Tyler Baicar <tbaicar@...eaurora.org>
> ---
> arch/arm/include/asm/kvm_arm.h | 1 +
> arch/arm/include/asm/system_misc.h | 5 +++++
> arch/arm/kvm/mmu.c | 15 +++++++++++++--
> arch/arm64/include/asm/kvm_arm.h | 1 +
> arch/arm64/include/asm/system_misc.h | 2 ++
> arch/arm64/mm/fault.c | 13 +++++++++++++
> 6 files changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
> index e22089f..33a77509 100644
> --- a/arch/arm/include/asm/kvm_arm.h
> +++ b/arch/arm/include/asm/kvm_arm.h
> @@ -187,6 +187,7 @@
> #define FSC_FAULT (0x04)
> #define FSC_ACCESS (0x08)
> #define FSC_PERM (0x0c)
> +#define FSC_EXTABT (0x10)
>
> /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
> #define HPFAR_MASK (~0xf)
> diff --git a/arch/arm/include/asm/system_misc.h b/arch/arm/include/asm/system_misc.h
> index a3d61ad..86e1faa 100644
> --- a/arch/arm/include/asm/system_misc.h
> +++ b/arch/arm/include/asm/system_misc.h
> @@ -24,4 +24,9 @@ extern unsigned int user_debug;
>
> #endif /* !__ASSEMBLY__ */
>
> +inline int handle_guest_sea(unsigned long addr, unsigned int esr)
> +{
> + return -1;
> +}
> +
> #endif /* __ASM_ARM_SYSTEM_MISC_H */
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index e9a5c0e..24cde84 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -29,6 +29,7 @@
> #include <asm/kvm_asm.h>
> #include <asm/kvm_emulate.h>
> #include <asm/virt.h>
> +#include <asm/system_misc.h>
>
> #include "trace.h"
>
> @@ -1441,8 +1442,18 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
>
> /* Check the stage-2 fault is trans. fault or write fault */
> fault_status = kvm_vcpu_trap_get_fault_type(vcpu);
> - if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
> - fault_status != FSC_ACCESS) {
> +
> + if (fault_status == FSC_EXTABT) {
> + if(handle_guest_sea((unsigned long)fault_ipa,
> + kvm_vcpu_get_hsr(vcpu))) {
> + kvm_err("Failed to handle guest SEA, FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
> + kvm_vcpu_trap_get_class(vcpu),
> + (unsigned long)kvm_vcpu_trap_get_fault(vcpu),
> + (unsigned long)kvm_vcpu_get_hsr(vcpu));
> + return -EFAULT;
> + }
> + } else if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
> + fault_status != FSC_ACCESS) {
> kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
> kvm_vcpu_trap_get_class(vcpu),
> (unsigned long)kvm_vcpu_trap_get_fault(vcpu),
> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> index 4b5c977..be0efb6 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -201,6 +201,7 @@
> #define FSC_FAULT ESR_ELx_FSC_FAULT
> #define FSC_ACCESS ESR_ELx_FSC_ACCESS
> #define FSC_PERM ESR_ELx_FSC_PERM
> +#define FSC_EXTABT ESR_ELx_FSC_EXTABT
>
> /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
> #define HPFAR_MASK (~UL(0xf))
> diff --git a/arch/arm64/include/asm/system_misc.h b/arch/arm64/include/asm/system_misc.h
> index 90daf4a..8522fff 100644
> --- a/arch/arm64/include/asm/system_misc.h
> +++ b/arch/arm64/include/asm/system_misc.h
> @@ -77,4 +77,6 @@ extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
> int sea_register_handler_chain(struct notifier_block *nb);
> void sea_unregister_handler_chain(struct notifier_block *nb);
>
> +int handle_guest_sea(unsigned long addr, unsigned int esr);
> +
> #endif /* __ASM_SYSTEM_MISC_H */
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index 81cb7ad..d714432 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -597,6 +597,19 @@ static const char *fault_name(unsigned int esr)
> }
>
> /*
> + * Handle Synchronous External Aborts that occur in a guest kernel.
> + */
> +int handle_guest_sea(unsigned long addr, unsigned int esr)
> +{
> + atomic_notifier_call_chain(&sea_handler_chain, 0, NULL);
> +
> + pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
> + fault_name(esr), esr, addr);
> +
> + return 0;
> +}
Don't we need to pass the abort to the guest?
Thanks,
Punit
> +
> +/*
> * Dispatch a data abort to the relevant handler.
> */
> asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
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