Re: [PATCH 0/2 v4] kdump,vmcoreinfo: Export the value of sme mask to vmcoreinfo
From: Dave Young
Date: Tue Dec 25 2018 - 22:34:09 EST
Add Kazu and Dave in cc
On 12/20/18 at 01:40pm, Lianbo Jiang wrote:
> This patchset did two things:
> a. add a new document for vmcoreinfo
> This document lists some variables that export to vmcoreinfo, and briefly
> describles what these variables indicate. It should be instructive for
> many people who do not know the vmcoreinfo, and it also normalizes the
> exported variable as a convention between kernel and use-space.
> b. export the value of sme mask to vmcoreinfo
> For AMD machine with SME feature, makedumpfile tools need to know whether
> the crash kernel was encrypted or not. If SME is enabled in the first
> kernel, the crash kernel's page table(pgd/pud/pmd/pte) contains the
> memory encryption mask, so need to remove the sme mask to obtain the true
> physical address.
> Changes since v1:
> 1. No need to export a kernel-internal mask to userspace, so copy the
> value of sme_me_mask to a local variable 'sme_mask' and write the value
> of sme_mask to vmcoreinfo.
> 2. Add comment for the code.
> 3. Improve the patch log.
> 4. Add the vmcoreinfo documentation.
> Changes since v2:
> 1. Improve the vmcoreinfo document, add more descripts for these
> variables exported.
> 2. Fix spelling errors in the document.
> Changes since v3:
> 1. Still improve the vmcoreinfo document, and make it become more
> clear and easy to read.
> 2. Move sme_mask comments in the code to the vmcoreinfo document.
> 3. Improve patch log.
> Lianbo Jiang (2):
> kdump: add the vmcoreinfo documentation
> kdump,vmcoreinfo: Export the value of sme mask to vmcoreinfo
> Documentation/kdump/vmcoreinfo.txt | 513 +++++++++++++++++++++++++++++
> arch/x86/kernel/machine_kexec_64.c | 3 +
> 2 files changed, 516 insertions(+)
> create mode 100644 Documentation/kdump/vmcoreinfo.txt