Re: [PATCH v7 3/3] x86: Make the GDT remapping read-only on 64-bit

[Pavel Machek]

On Tue 2017-03-14 10:05:08, Thomas Garnier wrote:
> This patch makes the GDT remapped pages read-only to prevent corruption.
> This change is done only on 64-bit.
> 
> The native_load_tr_desc function was adapted to correctly handle a
> read-only GDT. The LTR instruction always writes to the GDT TSS entry.
> This generates a page fault if the GDT is read-only. This change checks
> if the current GDT is a remap and swap GDTs as needed. This function was
> tested by booting multiple machines and checking hibernation works
> properly.
> 
> KVM SVM and VMX were adapted to use the writeable GDT. On VMX, the
> per-cpu variable was removed for functions to fetch the original GDT.
> Instead of reloading the previous GDT, VMX will reload the fixmap GDT as
> expected. For testing, VMs were started and restored on multiple
> configurations.
> 
> Signed-off-by: Thomas Garnier <thgarnie@xxxxxxxxxx>

Can we get the same change for 32-bit, too? Growing differences
between 32 and 64 bit are a bit of a problem...
								Pavel
								
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