On Thu, Apr 01, 2021 at 01:26:23PM -0700, Dave Hansen wrote: > On 2/5/21 3:38 PM, Kuppuswamy Sathyanarayanan wrote: > > From: "Kirill A. Shutemov" <kirill.shute...@linux.intel.com> > > > > All ioremap()ed paged that are not backed by normal memory (NONE or > > RESERVED) have to be mapped as shared. > > s/paged/pages/ > > > > +/* Make the page accesable by VMM */ > > +#define pgprot_tdx_shared(prot) __pgprot(pgprot_val(prot) | > > tdx_shared_mask()) > > + > > #ifndef __ASSEMBLY__ > > #include <asm/x86_init.h> > > #include <asm/fpu/xstate.h> > > diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c > > index 9e5ccc56f8e0..a0ba760866d4 100644 > > --- a/arch/x86/mm/ioremap.c > > +++ b/arch/x86/mm/ioremap.c > > @@ -87,12 +87,12 @@ static unsigned int __ioremap_check_ram(struct resource > > *res) > > } > > > > /* > > - * In a SEV guest, NONE and RESERVED should not be mapped encrypted because > > - * there the whole memory is already encrypted. > > + * In a SEV or TDX guest, NONE and RESERVED should not be mapped encrypted > > (or > > + * private in TDX case) because there the whole memory is already > > encrypted. > > */ > > But doesn't this mean that we can't ioremap() normal memory?
It's not allowed anyway: see (io_desc.flags & IORES_MAP_SYSTEM_RAM) in the __ioremap_caller(). > I was somehow expecting that we would need to do this for some > host<->guest communication pages. It goes though DMA API, not ioremap(). -- Kirill A. Shutemov
