+kexec-list On 3/6/2017 11:58 AM, Tom Lendacky wrote: > On 3/1/2017 3:25 AM, Dave Young wrote: >> Hi Tom, > > Hi Dave, > >> >> On 02/17/17 at 10:43am, Tom Lendacky wrote: >>> On 2/17/2017 9:57 AM, Konrad Rzeszutek Wilk wrote: >>>> On Thu, Feb 16, 2017 at 09:47:55AM -0600, Tom Lendacky wrote: >>>>> Provide support so that kexec can be used to boot a kernel when SME is >>>>> enabled. >>>> >>>> Is the point of kexec and kdump to ehh, dump memory ? But if the >>>> rest of the memory is encrypted you won't get much, will you? >>> >>> Kexec can be used to reboot a system without going back through BIOS. >>> So you can use kexec without using kdump. >>> >>> For kdump, just taking a quick look, the option to enable memory >>> encryption can be provided on the crash kernel command line and then >> >> Is there a simple way to get the SME status? Probably add some sysfs >> file for this purpose. > > Currently there is not. I can look at adding something, maybe just the > sme_me_mask value, which if non-zero, would indicate SME is active. > >> >>> crash kernel can would be able to copy the memory decrypted if the >>> pagetable is set up properly. It looks like currently ioremap_cache() >>> is used to map the old memory page. That might be able to be changed >>> to a memremap() so that the encryption bit is set in the mapping. That >>> will mean that memory that is not marked encrypted (EFI tables, swiotlb >>> memory, etc) would not be read correctly. >> >> Manage to store info about those ranges which are not encrypted so that >> memremap can handle them? > > I can look into whether something can be done in this area. Any input > you can provide as to what would be the best way/place to store the > range info so kdump can make use of it, would be greatly appreciated. > >> >>> >>>> >>>> Would it make sense to include some printk to the user if they >>>> are setting up kdump that they won't get anything out of it? >>> >>> Probably a good idea to add something like that. >> >> It will break kdump functionality, it should be fixed instead of >> just adding printk to warn user.. > > I do want kdump to work. I'll investigate further what can be done in > this area. > > Thanks, > Tom > >> >> Thanks >> Dave >>
