search

riscv-non-isa / riscv-iommu

RISC-V IOMMU Specification
https://jira.riscv.org/browse/RVG-55
Creative Commons Attribution 4.0 International
88 stars 17 forks source link

Is there a situation where DevATC stores SPA and the device is controlled by Guest OS? #249

Closed baimengwei closed 1 year ago

baimengwei commented 1 year ago

Under the control of the Guest OS, when the device initiates a VA or GPA address translation request, then the IOMMU determines that the address is related to the MSI, so IOMMU searches and returns the translation result.

According to the Process to translate addresses of MSIs, Which address will be returned to DevATC, is GPA or SPA ?

Or, Is there any SPA address that the Guest OS can perceive from address translation request and cached SPA in DevATC?

If the Guest OS can obtain any information about the SPA address, can it be guaranteed that no security issues will be caused?

ved-rivos commented 1 year ago

The deviceATC receives a GPA if the T2GPA control is active otherwise it receives a SPA. Typically use of ATS involves providing SPA to the device. Whether the device makes the SPA in the devATC available to software depends on the device. Typically devices do not do that but I cannot make a statement about all devices. Whether a device is secure and can be trusted is a determination that the platform administrator has to make. The IOMMU cannot provided any guarantees or make claims about the security of a device.

baimengwei commented 1 year ago

Whether a device is secure and can be trusted is a determination that the platform administrator has to make. The IOMMU cannot provided any guarantees or make claims about the security of a device.

Thanks.