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| author | Michael Kelley <mikelley@microsoft.com> | 2022-03-24 09:14:51 -0700 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2022-03-29 12:12:50 +0000 |
| commit | 37200078ed6aa2ac3c88a01a64996133dccfdd34 (patch) | |
| tree | f207568ffac02555c7909b4c0fcaa53c6cdbf212 /drivers/hv/hv_common.c | |
| parent | 792f232d57ff28bbd5f9c4abe0466b23d5879dc8 (diff) | |
| download | lwn-37200078ed6aa2ac3c88a01a64996133dccfdd34.tar.gz lwn-37200078ed6aa2ac3c88a01a64996133dccfdd34.zip | |
Drivers: hv: vmbus: Propagate VMbus coherence to each VMbus device
VMbus synthetic devices are not represented in the ACPI DSDT -- only
the top level VMbus device is represented. As a result, on ARM64
coherence information in the _CCA method is not specified for
synthetic devices, so they default to not hardware coherent.
Drivers for some of these synthetic devices have been recently
updated to use the standard DMA APIs, and they are incurring extra
overhead of unneeded software coherence management.
Fix this by propagating coherence information from the VMbus node
in ACPI to the individual synthetic devices. There's no effect on
x86/x64 where devices are always hardware coherent.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/1648138492-2191-2-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/hv/hv_common.c')
| -rw-r--r-- | drivers/hv/hv_common.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index 181d16bbf49d..820e81406251 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -20,6 +20,7 @@ #include <linux/panic_notifier.h> #include <linux/ptrace.h> #include <linux/slab.h> +#include <linux/dma-map-ops.h> #include <asm/hyperv-tlfs.h> #include <asm/mshyperv.h> @@ -216,6 +217,16 @@ bool hv_query_ext_cap(u64 cap_query) } EXPORT_SYMBOL_GPL(hv_query_ext_cap); +void hv_setup_dma_ops(struct device *dev, bool coherent) +{ + /* + * Hyper-V does not offer a vIOMMU in the guest + * VM, so pass 0/NULL for the IOMMU settings + */ + arch_setup_dma_ops(dev, 0, 0, NULL, coherent); +} +EXPORT_SYMBOL_GPL(hv_setup_dma_ops); + bool hv_is_hibernation_supported(void) { return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4); |