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Thu, 14 Jul 2022 23:11:41 -0700 (PDT) Date: Thu, 14 Jul 2022 23:10:24 -0700 In-Reply-To: <20220715061027.1612149-1-kaleshsingh@google.com> Message-Id: <20220715061027.1612149-16-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220715061027.1612149-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.37.0.170.g444d1eabd0-goog Subject: [PATCH v4 15/18] KVM: arm64: Implement non-protected nVHE hyp stack unwinder From: Kalesh Singh To: maz@kernel.org, mark.rutland@arm.com, broonie@kernel.org, madvenka@linux.microsoft.com Cc: will@kernel.org, qperret@google.com, tabba@google.com, kaleshsingh@google.com, james.morse@arm.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, andreyknvl@gmail.com, russell.king@oracle.com, vincenzo.frascino@arm.com, mhiramat@kernel.org, ast@kernel.org, drjones@redhat.com, wangkefeng.wang@huawei.com, elver@google.com, keirf@google.com, yuzenghui@huawei.com, ardb@kernel.org, oupton@google.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, android-mm@google.com, kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Implements the common framework necessary for unwind() to work for non-protected nVHE mode: - on_accessible_stack() - on_overflow_stack() - unwind_next() Non-protected nVHE unwind() is used to unwind and dump the hypervisor stacktrace by the host in EL1 Signed-off-by: Kalesh Singh --- arch/arm64/include/asm/stacktrace/nvhe.h | 67 +++++++++++++++++++++++- arch/arm64/kvm/arm.c | 2 +- 2 files changed, 66 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/stacktrace/nvhe.h b/arch/arm64/include/asm/stacktrace/nvhe.h index c7c8ac889ec1..c3f94b10f8f0 100644 --- a/arch/arm64/include/asm/stacktrace/nvhe.h +++ b/arch/arm64/include/asm/stacktrace/nvhe.h @@ -115,15 +115,78 @@ NOKPROBE_SYMBOL(unwind_next); * Non-protected nVHE HYP stack unwinder */ #else /* !__KVM_NVHE_HYPERVISOR__ */ +DECLARE_KVM_NVHE_PER_CPU(unsigned long [PAGE_SIZE/sizeof(long)], overflow_stack); +DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_stacktrace_info, kvm_stacktrace_info); +DECLARE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); + +/** + * kvm_nvhe_stack_kern_va - Convert KVM nVHE HYP stack addresses to a kernel VAs + * + * The nVHE hypervisor stack is mapped in the flexible 'private' VA range, to + * allow for guard pages below the stack. Consequently, the fixed offset address + * translation macros won't work here. + * + * The kernel VA is calculated as an offset from the kernel VA of the hypervisor + * stack base. + * + * Returns true on success and updates @addr to its corresponding kernel VA; + * otherwise returns false. + */ +static inline bool kvm_nvhe_stack_kern_va(unsigned long *addr, + enum stack_type type) +{ + struct kvm_nvhe_stacktrace_info *stacktrace_info; + unsigned long hyp_base, kern_base, hyp_offset; + + stacktrace_info = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info); + + switch (type) { + case STACK_TYPE_HYP: + kern_base = (unsigned long)*this_cpu_ptr(&kvm_arm_hyp_stack_page); + hyp_base = (unsigned long)stacktrace_info->stack_base; + break; + case STACK_TYPE_OVERFLOW: + kern_base = (unsigned long)this_cpu_ptr_nvhe_sym(overflow_stack); + hyp_base = (unsigned long)stacktrace_info->overflow_stack_base; + break; + default: + return false; + } + + hyp_offset = *addr - hyp_base; + + *addr = kern_base + hyp_offset; + + return true; +} + static inline bool on_overflow_stack(unsigned long sp, unsigned long size, struct stack_info *info) { - return false; + struct kvm_nvhe_stacktrace_info *stacktrace_info + = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info); + unsigned long low = (unsigned long)stacktrace_info->overflow_stack_base; + unsigned long high = low + OVERFLOW_STACK_SIZE; + + return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info); +} + +static inline bool on_hyp_stack(unsigned long sp, unsigned long size, + struct stack_info *info) +{ + struct kvm_nvhe_stacktrace_info *stacktrace_info + = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info); + unsigned long low = (unsigned long)stacktrace_info->stack_base; + unsigned long high = low + PAGE_SIZE; + + return on_stack(sp, size, low, high, STACK_TYPE_HYP, info); } static int notrace unwind_next(struct unwind_state *state) { - return 0; + struct stack_info info; + + return unwind_next_common(state, &info, kvm_nvhe_stack_kern_va); } NOKPROBE_SYMBOL(unwind_next); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index a0188144a122..6a64293108c5 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -49,7 +49,7 @@ DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized); DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector); -static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); +DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); unsigned long kvm_arm_hyp_percpu_base[NR_CPUS]; DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params); -- 2.37.0.170.g444d1eabd0-goog