Re: [PATCH] x86/tdx: Fix crash on kexec

[Kirill A. Shutemov]

On Sat, Jun 29, 2024 at 03:59:33PM +0200, Borislav Petkov wrote:
> On Sat, Jun 29, 2024 at 04:06:20PM +0300, Kirill A. Shutemov wrote:
> > The function tdx_enc_status_changed() was modified to handle vmalloc()
> > mappings. It now utilizes slow_virt_to_phys() to determine the physical
> > address of the page by walking page tables and looking for the physical
> > address in the page table entry.
> > 
> > However, this adjustment conflicted with the enabling of kexec. The
> > function tdx_kexec_finish() clears the page table entry before calling
> > tdx_enc_status_changed(), causing a BUG_ON() error in
> > slow_virt_to_phys().
> > 
> > To address this issue, tdx_enc_status_change() should use __pa() to
> > obtain physical addresses whenever possible. The virt_addr_valid() check
> > will handle such cases, while any other scenarios, including vmalloc()
> > mappings, will resort to slow_virt_to_phys().
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> > Fixes: e1b8ac3aae58 ("x86/tdx: Support vmalloc() for tdx_enc_status_changed()")
> 
> I'm going to zap this one from x86/urgent and give you guys ample time to test
> thus stuff better and longer.
> 
> Also, what is this e1b8ac3aae58 fixing and why is it urgent?

Daxuan, how urgent is this fix for you?

-- 
  Kiryl Shutsemau / Kirill A. Shutemov