From a494aef23dfc732945cb42e22246a5c31174e4a5 Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Thu, 20 Apr 2023 18:30:25 -0700 Subject: [PATCH] PCI: hv: Replace retarget_msi_interrupt_params with hyperv_pcpu_input_arg 4 commits are involved here: A (2016): commit 0de8ce3ee8e3 ("PCI: hv: Allocate physically contiguous hypercall params buffer") B (2017): commit be66b6736591 ("PCI: hv: Use page allocation for hbus structure") C (2019): commit 877b911a5ba0 ("PCI: hv: Avoid a kmemleak false positive caused by the hbus buffer") D (2018): commit 68bb7bfb7985 ("X86/Hyper-V: Enable IPI enlightenments") Patch D introduced the per-CPU hypercall input page "hyperv_pcpu_input_arg" in 2018. With patch D, we no longer need the per-Hyper-V-PCI-bus hypercall input page "hbus->retarget_msi_interrupt_params" that was added in patch A, and the issue addressed by patch B is no longer an issue, and we can also get rid of patch C. The change here is required for PCI device assignment to work for Confidential VMs (CVMs) running without a paravisor, because otherwise we would have to call set_memory_decrypted() for "hbus->retarget_msi_interrupt_params" before calling the hypercall HVCALL_RETARGET_INTERRUPT. Signed-off-by: Dexuan Cui Reviewed-by: Michael Kelley Acked-by: Lorenzo Pieralisi Link: https://lore.kernel.org/r/20230421013025.17152-1-decui@microsoft.com Signed-off-by: Wei Liu --- drivers/pci/controller/pci-hyperv.c | 48 ++++++------------------------------- 1 file changed, 7 insertions(+), 41 deletions(-) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index 337f3b4..bc32662 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -508,20 +508,11 @@ struct hv_pcibus_device { struct msi_domain_info msi_info; struct irq_domain *irq_domain; - spinlock_t retarget_msi_interrupt_lock; - struct workqueue_struct *wq; /* Highest slot of child device with resources allocated */ int wslot_res_allocated; bool use_calls; /* Use hypercalls to access mmio cfg space */ - - /* hypercall arg, must not cross page boundary */ - struct hv_retarget_device_interrupt retarget_msi_interrupt_params; - - /* - * Don't put anything here: retarget_msi_interrupt_params must be last - */ }; /* @@ -645,9 +636,9 @@ static void hv_arch_irq_unmask(struct irq_data *data) hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata); int_desc = data->chip_data; - spin_lock_irqsave(&hbus->retarget_msi_interrupt_lock, flags); + local_irq_save(flags); - params = &hbus->retarget_msi_interrupt_params; + params = *this_cpu_ptr(hyperv_pcpu_input_arg); memset(params, 0, sizeof(*params)); params->partition_id = HV_PARTITION_ID_SELF; params->int_entry.source = HV_INTERRUPT_SOURCE_MSI; @@ -680,7 +671,7 @@ static void hv_arch_irq_unmask(struct irq_data *data) if (!alloc_cpumask_var(&tmp, GFP_ATOMIC)) { res = 1; - goto exit_unlock; + goto out; } cpumask_and(tmp, dest, cpu_online_mask); @@ -689,7 +680,7 @@ static void hv_arch_irq_unmask(struct irq_data *data) if (nr_bank <= 0) { res = 1; - goto exit_unlock; + goto out; } /* @@ -708,8 +699,8 @@ static void hv_arch_irq_unmask(struct irq_data *data) res = hv_do_hypercall(HVCALL_RETARGET_INTERRUPT | (var_size << 17), params, NULL); -exit_unlock: - spin_unlock_irqrestore(&hbus->retarget_msi_interrupt_lock, flags); +out: + local_irq_restore(flags); /* * During hibernation, when a CPU is offlined, the kernel tries @@ -3598,35 +3589,11 @@ static int hv_pci_probe(struct hv_device *hdev, bool enter_d0_retry = true; int ret; - /* - * hv_pcibus_device contains the hypercall arguments for retargeting in - * hv_irq_unmask(). Those must not cross a page boundary. - */ - BUILD_BUG_ON(sizeof(*hbus) > HV_HYP_PAGE_SIZE); - bridge = devm_pci_alloc_host_bridge(&hdev->device, 0); if (!bridge) return -ENOMEM; - /* - * With the recent 59bb47985c1d ("mm, sl[aou]b: guarantee natural - * alignment for kmalloc(power-of-two)"), kzalloc() is able to allocate - * a 4KB buffer that is guaranteed to be 4KB-aligned. Here the size and - * alignment of hbus is important because hbus's field - * retarget_msi_interrupt_params must not cross a 4KB page boundary. - * - * Here we prefer kzalloc to get_zeroed_page(), because a buffer - * allocated by the latter is not tracked and scanned by kmemleak, and - * hence kmemleak reports the pointer contained in the hbus buffer - * (i.e. the hpdev struct, which is created in new_pcichild_device() and - * is tracked by hbus->children) as memory leak (false positive). - * - * If the kernel doesn't have 59bb47985c1d, get_zeroed_page() *must* be - * used to allocate the hbus buffer and we can avoid the kmemleak false - * positive by using kmemleak_alloc() and kmemleak_free() to ask - * kmemleak to track and scan the hbus buffer. - */ - hbus = kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL); + hbus = kzalloc(sizeof(*hbus), GFP_KERNEL); if (!hbus) return -ENOMEM; @@ -3683,7 +3650,6 @@ static int hv_pci_probe(struct hv_device *hdev, INIT_LIST_HEAD(&hbus->dr_list); spin_lock_init(&hbus->config_lock); spin_lock_init(&hbus->device_list_lock); - spin_lock_init(&hbus->retarget_msi_interrupt_lock); hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0, hbus->bridge->domain_nr); if (!hbus->wq) { -- 2.7.4