16 Jun
2023
16 Jun
'23
2:29 a.m.
From: Jason Gunthorpe jgg@nvidia.com Sent: Wednesday, June 14, 2023 7:53 PM
On Wed, Jun 14, 2023 at 08:07:30AM +0000, Tian, Kevin wrote:
think of a scenario where the vbios memory is shared by multiple qemu instances then RW allows a malicious VM to modify the shared content then potentially attacking other VMs.
qemu would have to map the vbios as MAP_PRIVATE WRITE before the iommu side could map it writable, so this is not a real worry.
Make sense.
but IMHO it's still safer to reduce the permission (RO->NP) than increasing the permission (RO->RW) when faithfully emulating bare metal behavior is impossible, especially when there is no real usage counting on it. 😊