| Message ID | 20241004144307.66199-8-steven.price@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: Support for running as a guest in Arm CCA | expand |
On 10/5/24 12:43 AM, Steven Price wrote: > Within a realm guest it's not possible for a device emulated by the VMM > to access arbitrary guest memory. So force the use of bounce buffers to > ensure that the memory the emulated devices are accessing is in memory > which is explicitly shared with the host. > > This adds a call to swiotlb_update_mem_attributes() which calls > set_memory_decrypted() to ensure the bounce buffer memory is shared with > the host. For non-realm guests or hosts this is a no-op. > > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > Signed-off-by: Steven Price <steven.price@arm.com> > --- > v3: Simplify mem_init() by using a 'flags' variable. > --- > arch/arm64/kernel/rsi.c | 1 + > arch/arm64/mm/init.c | 10 +++++++++- > 2 files changed, 10 insertions(+), 1 deletion(-) > Reviewed-by: Gavin Shan <gshan@redhat.com>
diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c index f1add76f89ce..58408f5add49 100644 --- a/arch/arm64/kernel/rsi.c +++ b/arch/arm64/kernel/rsi.c @@ -6,6 +6,7 @@ #include <linux/jump_label.h> #include <linux/memblock.h> #include <linux/psci.h> +#include <linux/swiotlb.h> #include <asm/io.h> #include <asm/rsi.h> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 27a32ff15412..d21f67d67cf5 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -41,6 +41,7 @@ #include <asm/kvm_host.h> #include <asm/memory.h> #include <asm/numa.h> +#include <asm/rsi.h> #include <asm/sections.h> #include <asm/setup.h> #include <linux/sizes.h> @@ -366,8 +367,14 @@ void __init bootmem_init(void) */ void __init mem_init(void) { + unsigned int flags = SWIOTLB_VERBOSE; bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit); + if (is_realm_world()) { + swiotlb = true; + flags |= SWIOTLB_FORCE; + } + if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb) { /* * If no bouncing needed for ZONE_DMA, reduce the swiotlb @@ -379,7 +386,8 @@ void __init mem_init(void) swiotlb = true; } - swiotlb_init(swiotlb, SWIOTLB_VERBOSE); + swiotlb_init(swiotlb, flags); + swiotlb_update_mem_attributes(); /* this will put all unused low memory onto the freelists */ memblock_free_all();