When using VHE, the host needs to clear HCR_EL2.TGE bit in order to interact with guest TLBs, switching from EL2&0 translation regime to EL1&0.

However, some non-maskable asynchronous event could happen while TGE is cleared like SDEI. Because of this address translation operations relying on EL2&0 translation regime could fail (tlb invalidation, userspace access, ...).

Fix this by properly setting HCR_EL2.TGE when entering NMI context and clear it if necessary when returning to the interrupted context.

Signed-off-by: Julien Thierry julien.thierry@arm.com Suggested-by: Marc Zyngier marc.zyngier@arm.com Reviewed-by: Marc Zyngier marc.zyngier@arm.com Reviewed-by: James Morse james.morse@arm.com Cc: Arnd Bergmann arnd@arndb.de Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will.deacon@arm.com Cc: Marc Zyngier marc.zyngier@arm.com Cc: James Morse james.morse@arm.com Cc: linux-arch@vger.kernel.org Cc: stable@vger.kernel.org --- arch/arm64/include/asm/hardirq.h | 31 +++++++++++++++++++++++++++++++ arch/arm64/kernel/irq.c | 3 +++ include/linux/hardirq.h | 7 +++++++ 3 files changed, 41 insertions(+)

diff --git a/arch/arm64/include/asm/hardirq.h b/arch/arm64/include/asm/hardirq.h index 1473fc2..89691c8 100644 --- a/arch/arm64/include/asm/hardirq.h +++ b/arch/arm64/include/asm/hardirq.h @@ -17,8 +17,12 @@ #define __ASM_HARDIRQ_H

#include <linux/cache.h> +#include <linux/percpu.h> #include <linux/threads.h> +#include <asm/barrier.h> #include <asm/irq.h> +#include <asm/kvm_arm.h> +#include <asm/sysreg.h>

#define NR_IPI 7

@@ -37,6 +41,33 @@

#define __ARCH_IRQ_EXIT_IRQS_DISABLED 1

+struct nmi_ctx { + u64 hcr; +}; + +DECLARE_PER_CPU(struct nmi_ctx, nmi_contexts); + +#define arch_nmi_enter() \ + do { \ + if (is_kernel_in_hyp_mode()) { \ + struct nmi_ctx *nmi_ctx = this_cpu_ptr(&nmi_contexts); \ + nmi_ctx->hcr = read_sysreg(hcr_el2); \ + if (!(nmi_ctx->hcr & HCR_TGE)) { \ + write_sysreg(nmi_ctx->hcr | HCR_TGE, hcr_el2); \ + isb(); \ + } \ + } \ + } while (0) + +#define arch_nmi_exit() \ + do { \ + if (is_kernel_in_hyp_mode()) { \ + struct nmi_ctx *nmi_ctx = this_cpu_ptr(&nmi_contexts); \ + if (!(nmi_ctx->hcr & HCR_TGE)) \ + write_sysreg(nmi_ctx->hcr, hcr_el2); \ + } \ + } while (0) + static inline void ack_bad_irq(unsigned int irq) { extern unsigned long irq_err_count; diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c index 780a12f..92fa817 100644 --- a/arch/arm64/kernel/irq.c +++ b/arch/arm64/kernel/irq.c @@ -33,6 +33,9 @@

unsigned long irq_err_count;

+/* Only access this in an NMI enter/exit */ +DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts); + DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);

int arch_show_interrupts(struct seq_file *p, int prec) diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 0fbbcdf..da0af63 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -60,8 +60,14 @@ static inline void rcu_nmi_exit(void) */ extern void irq_exit(void);

+#ifndef arch_nmi_enter +#define arch_nmi_enter() do { } while (0) +#define arch_nmi_exit() do { } while (0) +#endif + #define nmi_enter() \ do { \ + arch_nmi_enter(); \ printk_nmi_enter(); \ lockdep_off(); \ ftrace_nmi_enter(); \ @@ -80,6 +86,7 @@ static inline void rcu_nmi_exit(void) ftrace_nmi_exit(); \ lockdep_on(); \ printk_nmi_exit(); \ + arch_nmi_exit(); \ } while (0)

#endif /* LINUX_HARDIRQ_H */