From cdc6f2e0c9fcef2027f4fc5f25ddd15e36283e90 Mon Sep 17 00:00:00 2001 From: Cédric Le Goater Date: Thu, 6 Feb 2025 14:14:31 +0100 Subject: vfio: Rephrase comment in vfio_listener_region_add() error path MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Rephrase a bit the ending comment about how errors are handled depending on the phase in which vfio_listener_region_add() is called. Reviewed-by: Alex Williamson Link: https://lore.kernel.org/qemu-devel/20250206131438.1505542-4-clg@redhat.com Signed-off-by: Cédric Le Goater --- hw/vfio/common.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'hw/vfio/common.c') diff --git a/hw/vfio/common.c b/hw/vfio/common.c index f7499a9b74..62af1216fc 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -683,12 +683,13 @@ fail: error_reportf_err(err, "PCI p2p may not work: "); return; } - /* - * On the initfn path, store the first error in the container so we - * can gracefully fail. Runtime, there's not much we can do other - * than throw a hardware error. - */ + if (!bcontainer->initialized) { + /* + * At machine init time or when the device is attached to the + * VM, store the first error in the container so we can + * gracefully fail the device realize routine. + */ if (!bcontainer->error) { error_propagate_prepend(&bcontainer->error, err, "Region %s: ", @@ -697,6 +698,10 @@ fail: error_free(err); } } else { + /* + * At runtime, there's not much we can do other than throw a + * hardware error. + */ error_report_err(err); hw_error("vfio: DMA mapping failed, unable to continue"); } -- cgit 1.4.1 From aaec00422ba6538ca3e6bfa612bbae155ec15c84 Mon Sep 17 00:00:00 2001 From: Cédric Le Goater Date: Thu, 6 Feb 2025 14:14:33 +0100 Subject: vfio: Improve error reporting when MMIO region mapping fails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When the IOMMU address space width is smaller than the physical address width, a MMIO region of a device can fail to map because the region is outside the supported IOVA ranges of the VM. In this case, PCI peer-to-peer transactions on BARs are not supported. This can occur with the 39-bit IOMMU address space width, as can be the case on some Intel consumer processors, or when using a vIOMMU device with default settings. The current error message is unclear, improve it and also change the error report to a warning because it is a non fatal condition for the VM. To prevent excessive log messages, restrict these recurring DMA mapping errors to a single warning at runtime. Reviewed-by: Alex Williamson Link: https://lore.kernel.org/qemu-devel/20250206131438.1505542-6-clg@redhat.com Signed-off-by: Cédric Le Goater --- hw/vfio/common.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'hw/vfio/common.c') diff --git a/hw/vfio/common.c b/hw/vfio/common.c index 62af1216fc..4fca4c6166 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -555,6 +555,18 @@ static bool vfio_get_section_iova_range(VFIOContainerBase *bcontainer, return true; } +static void vfio_device_error_append(VFIODevice *vbasedev, Error **errp) +{ + /* + * MMIO region mapping failures are not fatal but in this case PCI + * peer-to-peer transactions are broken. + */ + if (vbasedev && vbasedev->type == VFIO_DEVICE_TYPE_PCI) { + error_append_hint(errp, "%s: PCI peer-to-peer transactions " + "on BARs are not supported.\n", vbasedev->name); + } +} + static void vfio_listener_region_add(MemoryListener *listener, MemoryRegionSection *section) { @@ -670,7 +682,10 @@ static void vfio_listener_region_add(MemoryListener *listener, strerror(-ret)); if (memory_region_is_ram_device(section->mr)) { /* Allow unexpected mappings not to be fatal for RAM devices */ - error_report_err(err); + VFIODevice *vbasedev = + vfio_get_vfio_device(memory_region_owner(section->mr)); + vfio_device_error_append(vbasedev, &err); + warn_report_err_once(err); return; } goto fail; -- cgit 1.4.1 From be7d8579eb5758c0edf81eb068017a56471a77e0 Mon Sep 17 00:00:00 2001 From: Cédric Le Goater Date: Thu, 6 Feb 2025 14:14:35 +0100 Subject: vfio: Remove superfluous error report in vfio_listener_region_add() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit For pseries machines, commit 567b5b309abe ("vfio/pci: Relax DMA map errors for MMIO regions") introduced 2 error reports to notify the user of MMIO mapping errors. Consolidate both code paths under one. Cc: Harsh Prateek Bora Cc: Shivaprasad G Bhat Reviewed-by: Harsh Prateek Bora Reviewed-by: Alex Williamson Link: https://lore.kernel.org/qemu-devel/20250206131438.1505542-8-clg@redhat.com Signed-off-by: Cédric Le Goater --- hw/vfio/common.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'hw/vfio/common.c') diff --git a/hw/vfio/common.c b/hw/vfio/common.c index 4fca4c6166..abbdc56b6d 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -594,8 +594,9 @@ static void vfio_listener_region_add(MemoryListener *listener, return; } + /* PPC64/pseries machine only */ if (!vfio_container_add_section_window(bcontainer, section, &err)) { - goto fail; + goto mmio_dma_error; } memory_region_ref(section->mr); @@ -680,6 +681,7 @@ static void vfio_listener_region_add(MemoryListener *listener, "0x%"HWADDR_PRIx", %p) = %d (%s)", bcontainer, iova, int128_get64(llsize), vaddr, ret, strerror(-ret)); + mmio_dma_error: if (memory_region_is_ram_device(section->mr)) { /* Allow unexpected mappings not to be fatal for RAM devices */ VFIODevice *vbasedev = @@ -694,11 +696,6 @@ static void vfio_listener_region_add(MemoryListener *listener, return; fail: - if (memory_region_is_ram_device(section->mr)) { - error_reportf_err(err, "PCI p2p may not work: "); - return; - } - if (!bcontainer->initialized) { /* * At machine init time or when the device is attached to the @@ -806,6 +803,7 @@ static void vfio_listener_region_del(MemoryListener *listener, memory_region_unref(section->mr); + /* PPC64/pseries machine only */ vfio_container_del_section_window(bcontainer, section); } -- cgit 1.4.1