Hi Konrad, Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> writes: > On 27.03.2024 9:09 PM, Volodymyr Babchuk wrote: >> It appears that hardware does not like cacheable accesses to this >> region. Trying to access this shared memory region as Normal Memory >> leads to secure interrupt which causes an endless loop somewhere in >> Trust Zone. >> >> The only reason it is working right now is because Qualcomm Hypervisor >> maps the same region as Non-Cacheable memory in Stage 2 translation >> tables. The issue manifests if we want to use another hypervisor (like >> Xen or KVM), which does not know anything about those specific >> mappings. This patch fixes the issue by mapping the shared memory as >> Write-Through. This removes dependency on correct mappings in Stage 2 >> tables. >> >> I tested this on SA8155P with Xen. >> >> Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx> >> --- > > Interesting.. > > +Doug, Rob have you ever seen this on Chrome? (FYI, Volodymyr, chromebooks > ship with no qcom hypervisor) Well, maybe I was wrong when called this thing "hypervisor". All I know that it sits in hyp.mbn partition and all what it does is setup EL2 before switching to EL1 and running UEFI. In my experiments I replaced contents of hyp.mbn with U-Boot, which gave me access to EL2 and I was able to boot Xen and then Linux as Dom0. -- WBR, Volodymyr
