From: Eillon <[email protected]> Once the buffer is full, hardware stops promoting writable-clean descriptors and raises a stage-2 Permission fault with ESR_EL2.ISS2.HDBSSF instead. Failed HDBSS accesses, such as external aborts and granule protection faults, are reported the same way.
Dispatch from kvm_handle_guest_abort() via the new esr_iss2_is_hdbssf() helper. FSC == OK means the exit path already flushed, so resume the guest; any other FSC is an error - clear it and report -EFAULT. Signed-off-by: Eillon <[email protected]> Signed-off-by: Tian Zheng <[email protected]> --- arch/arm64/include/asm/esr.h | 5 +++++ arch/arm64/include/asm/kvm_dirty_bit.h | 1 + arch/arm64/kvm/dirty_bit.c | 29 ++++++++++++++++++++++++++ arch/arm64/kvm/mmu.c | 4 ++++ 4 files changed, 39 insertions(+) diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h index f816f5d77f1a..4b3ccd407faa 100644 --- a/arch/arm64/include/asm/esr.h +++ b/arch/arm64/include/asm/esr.h @@ -437,6 +437,11 @@ #ifndef __ASSEMBLER__ #include <asm/types.h> +static inline bool esr_iss2_is_hdbssf(unsigned long esr) +{ + return !!(ESR_ELx_ISS2(esr) & ESR_ELx_HDBSSF); +} + static inline unsigned long esr_brk_comment(unsigned long esr) { return esr & ESR_ELx_BRK64_ISS_COMMENT_MASK; diff --git a/arch/arm64/include/asm/kvm_dirty_bit.h b/arch/arm64/include/asm/kvm_dirty_bit.h index d828e6b43fe9..eb2039820777 100644 --- a/arch/arm64/include/asm/kvm_dirty_bit.h +++ b/arch/arm64/include/asm/kvm_dirty_bit.h @@ -39,5 +39,6 @@ static inline bool vcpu_hdbss_enabled(struct kvm_vcpu *vcpu) int kvm_arm_vcpu_alloc_hdbss(struct kvm_vcpu *vcpu); void kvm_arm_vcpu_free_hdbss(struct kvm_vcpu *vcpu); void kvm_flush_hdbss_buffer(struct kvm_vcpu *vcpu); +int kvm_handle_hdbss_fault(struct kvm_vcpu *vcpu); #endif /* __ARM64_KVM_DIRTY_BIT_H__ */ diff --git a/arch/arm64/kvm/dirty_bit.c b/arch/arm64/kvm/dirty_bit.c index be0d12555c84..893a8c4248bc 100644 --- a/arch/arm64/kvm/dirty_bit.c +++ b/arch/arm64/kvm/dirty_bit.c @@ -98,3 +98,32 @@ void kvm_flush_hdbss_buffer(struct kvm_vcpu *vcpu) vcpu->arch.hdbss.hdbssprod_el2 = prod; isb(); } + +int kvm_handle_hdbss_fault(struct kvm_vcpu *vcpu) +{ + u64 prod; + u64 fsc; + + if (WARN_ON_ONCE(!system_supports_hdbss())) + return -EFAULT; + + if (WARN_ON_ONCE(!vcpu_hdbss_enabled(vcpu))) + return -EFAULT; + + prod = read_sysreg_s(SYS_HDBSSPROD_EL2); + fsc = FIELD_GET(HDBSSPROD_EL2_FSC_MASK, prod); + + if (fsc == HDBSSPROD_EL2_FSC_OK) + /* Buffer full: the exit path drained it before handle_exit. */ + return 1; + + if (fsc != HDBSSPROD_EL2_FSC_ExternalAbort && + fsc != HDBSSPROD_EL2_FSC_GPF) + WARN_ONCE(1, + "Unexpected HDBSS fault type, FSC: 0x%llx (prod=0x%llx, vcpu=%d)\n", + fsc, prod, vcpu->vcpu_id); + + /* Clear FSC so hardware dirty state updates can resume. */ + write_sysreg_s(prod & ~HDBSSPROD_EL2_FSC_MASK, SYS_HDBSSPROD_EL2); + return -EFAULT; +} diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 85a98d2c23a9..7bf82d65041c 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -15,6 +15,7 @@ #include <asm/pgalloc.h> #include <asm/cacheflush.h> #include <asm/kvm_arm.h> +#include <asm/kvm_dirty_bit.h> #include <asm/kvm_mmu.h> #include <asm/kvm_pgtable.h> #include <asm/kvm_pkvm.h> @@ -2315,6 +2316,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) is_iabt = kvm_vcpu_trap_is_iabt(vcpu); + if (esr_iss2_is_hdbssf(esr)) + return kvm_handle_hdbss_fault(vcpu); + if (esr_fsc_is_translation_fault(esr)) { /* Beyond sanitised PARange (which is the IPA limit) */ if (fault_ipa >= BIT_ULL(get_kvm_ipa_limit())) { -- 2.43.0
