On 12/10/2021 9:25 PM, Tianyu Lan wrote:
@@ -319,8 +320,16 @@ static void __init ms_hyperv_init_platform(void)
pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B
0x%x\n",
ms_hyperv.isolation_config_a,
ms_hyperv.isolation_config_b);
- if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP)
+ if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {
static_branch_enable(&isolation_type_snp);
+ swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary;
+ }
+
+ /*
+ * Enable swiotlb force mode in Isolation VM to
+ * use swiotlb bounce buffer for dma transaction.
+ */
+ swiotlb_force = SWIOTLB_FORCE;
I'm good with this approach that directly updates the swiotlb settings
here
rather than in IOMMU initialization code. It's a lot more
straightforward.
However, there's an issue if building for X86_32 without PAE, in that the
swiotlb module may not be built, resulting in compile and link
errors. The
swiotlb.h file needs to be updated to provide a stub function for
swiotlb_update_mem_attributes(). swiotlb_unencrypted_base probably
needs wrapper functions to get/set it, which can be stubs when
CONFIG_SWIOTLB is not set. swiotlb_force is a bit of a mess in that
it already
has a stub definition that assumes it will only be read, and not set.
A bit of
thinking will be needed to sort that out.
It's ok to fix the issue via selecting swiotlb when CONFIG_HYPERV is
set?
Sorry. ignore the previous statement. These codes doesn't depend on
CONFIG_HYPERV.
How about making these code under #ifdef CONFIG_X86_64 or CONFIG_SWIOTLB?
