When NX sees a fault on the user space buffer, generates a fault interrupt and pHyp forwards that interrupt to OS. Then the kernel makes H_GET_NX_FAULT HCALL to retrieve the fault CRB information. This patch adds changes to setup IRQ per each window and handles fault by updating CSB. Signed-off-by: Haren Myneni <haren@xxxxxxxxxxxxx> --- arch/powerpc/platforms/pseries/vas.c | 111 ++++++++++++++++++++++++++- 1 file changed, 110 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c index 0ade0d6d728f..2106eca0862a 100644 --- a/arch/powerpc/platforms/pseries/vas.c +++ b/arch/powerpc/platforms/pseries/vas.c @@ -224,6 +224,62 @@ int plpar_vas_query_capabilities(const u64 hcall, u8 query_type, } EXPORT_SYMBOL_GPL(plpar_vas_query_capabilities); +/* + * HCALL to get fault CRB from pHyp. + */ +static int plpar_get_nx_fault(u32 winid, u64 buffer) +{ + int64_t rc; + + rc = plpar_hcall_norets(H_GET_NX_FAULT, winid, buffer); + + switch (rc) { + case H_SUCCESS: + return 0; + case H_PARAMETER: + pr_err("HCALL(%x): Invalid window ID %u\n", H_GET_NX_FAULT, + winid); + return -EINVAL; + case H_STATE: + pr_err("HCALL(%x): No outstanding faults for window ID %u\n", + H_GET_NX_FAULT, winid); + return -EINVAL; + case H_PRIVILEGE: + pr_err("HCALL(%x): Window(%u): Invalid fault buffer 0x%llx\n", + H_GET_NX_FAULT, winid, buffer); + return -EACCES; + default: + pr_err("HCALL(%x): Unexpected error %lld for window(%u)\n", + H_GET_NX_FAULT, rc, winid); + return -EIO; + } +} + +/* + * Handle the fault interrupt. + * When the fault interrupt is received for each window, query pHyp to get + * the fault CRB on the specific fault. Then process the CRB by updating + * CSB or send signal if the user space CSB is invalid. + * Note: pHyp forwards an interrupt for each fault request. So one fault + * CRB to process for each H_GET_NX_FAULT HCALL. + */ +irqreturn_t pseries_vas_fault_thread_fn(int irq, void *data) +{ + struct vas_window *txwin = data; + struct coprocessor_request_block crb; + struct vas_win_task *tsk; + int rc; + + rc = plpar_get_nx_fault(txwin->winid, (u64)virt_to_phys(&crb)); + if (!rc) { + tsk = &txwin->task; + vas_dump_crb(&crb); + vas_update_csb(&crb, tsk); + } + + return IRQ_HANDLED; +} + /* * Allocate window and setup IRQ mapping. */ @@ -235,10 +291,51 @@ static int allocate_setup_window(struct vas_window *txwin, rc = plpar_vas_allocate_window(txwin, domain, wintype, DEF_WIN_CREDS); if (rc) return rc; + /* + * On powerVM, pHyp setup and forwards the fault interrupt per + * window. So the IRQ setup and fault handling will be done for + * each open window separately. + */ + txwin->lpar.fault_virq = irq_create_mapping(NULL, + txwin->lpar.fault_irq); + if (!txwin->lpar.fault_virq) { + pr_err("Failed irq mapping %d\n", txwin->lpar.fault_irq); + rc = -EINVAL; + goto out_win; + } + + txwin->lpar.name = kasprintf(GFP_KERNEL, "vas-win-%d", txwin->winid); + if (!txwin->lpar.name) { + rc = -ENOMEM; + goto out_irq; + } + + rc = request_threaded_irq(txwin->lpar.fault_virq, NULL, + pseries_vas_fault_thread_fn, IRQF_ONESHOT, + txwin->lpar.name, txwin); + if (rc) { + pr_err("VAS-Window[%d]: Request IRQ(%u) failed with %d\n", + txwin->winid, txwin->lpar.fault_virq, rc); + goto out_free; + } txwin->wcreds_max = DEF_WIN_CREDS; return 0; +out_free: + kfree(txwin->lpar.name); +out_irq: + irq_dispose_mapping(txwin->lpar.fault_virq); +out_win: + plpar_vas_deallocate_window(txwin->winid); + return rc; +} + +static inline void free_irq_setup(struct vas_window *txwin) +{ + free_irq(txwin->lpar.fault_virq, txwin); + irq_dispose_mapping(txwin->lpar.fault_virq); + kfree(txwin->lpar.name); } static struct vas_window *vas_allocate_window(struct vas_tx_win_open_attr *uattr, @@ -346,6 +443,11 @@ static struct vas_window *vas_allocate_window(struct vas_tx_win_open_attr *uattr return txwin; out_free: + /* + * Window is not operational. Free IRQ before closing + * window so that do not have to hold mutex. + */ + free_irq_setup(txwin); plpar_vas_deallocate_window(txwin->winid); out: atomic_dec(&ct_capab->used_lpar_creds); @@ -364,9 +466,16 @@ static int deallocate_free_window(struct vas_window *win) { int rc = 0; + /* + * Free IRQ after executing H_DEALLOCATE_VAS_WINDOW HCALL + * to close the window. pHyp waits for all requests including + * faults are processed before closing the window - Means all + * credits are returned. In the case of fault request, credit + * is returned after OS issues H_GET_NX_FAULT HCALL. + */ rc = plpar_vas_deallocate_window(win->winid); if (!rc) - kfree(win->lpar.name); + free_irq_setup(win); return rc; } -- 2.18.2