Messages in this thread Patch in this message |  | | Subject | Re: [RFC v1 22/26] x86/tdx: Exclude Shared bit from __PHYSICAL_MASK | From | Dave Hansen <> | Date | Thu, 1 Apr 2021 13:13:16 -0700 |
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On 2/5/21 3:38 PM, Kuppuswamy Sathyanarayanan wrote: > From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> > > tdx_shared_mask() returns the mask that has to be set in page table > entry to make page shared with VMM.
Needs to be either:
has to be set in a page table entry or has to be set in page table entries
Pick one, please. But, the grammar is wrong as-is.
> index 8fa654d61ac2..f10a00c4ad7f 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -875,6 +875,7 @@ config INTEL_TDX_GUEST > select PARAVIRT_XL > select X86_X2APIC > select SECURITY_LOCKDOWN_LSM > + select X86_MEM_ENCRYPT_COMMON > help > Provide support for running in a trusted domain on Intel processors > equipped with Trusted Domain eXtenstions. TDX is an new Intel > diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h > index b46ae140e39b..9bbfe6520ea4 100644 > --- a/arch/x86/include/asm/tdx.h > +++ b/arch/x86/include/asm/tdx.h > @@ -104,5 +104,6 @@ long tdx_kvm_hypercall3(unsigned int nr, unsigned long p1, unsigned long p2, > long tdx_kvm_hypercall4(unsigned int nr, unsigned long p1, unsigned long p2, > unsigned long p3, unsigned long p4); > > +phys_addr_t tdx_shared_mask(void);
I know it's redundant, but extern this, please. Ditto for all the other declarations in that header.
> #endif > #endif /* _ASM_X86_TDX_H */ > diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c > index ae37498df981..9681f4a0b4e0 100644 > --- a/arch/x86/kernel/tdx.c > +++ b/arch/x86/kernel/tdx.c > @@ -41,6 +41,11 @@ bool is_tdx_guest(void) > } > EXPORT_SYMBOL_GPL(is_tdx_guest); > > +phys_addr_t tdx_shared_mask(void) > +{ > + return 1ULL << (td_info.gpa_width - 1); > +}
A comment would be helpful:
/* The highest bit of a guest physical address is the "sharing" bit */
> static void tdx_get_info(void) > { > register long rcx asm("rcx"); > @@ -56,6 +61,9 @@ static void tdx_get_info(void) > > td_info.gpa_width = rcx & GENMASK(5, 0); > td_info.attributes = rdx; > + > + /* Exclude Shared bit from the __PHYSICAL_MASK */ > + physical_mask &= ~tdx_shared_mask(); > }
I wish we had all of these 'physical_mask' manipulations in a single spot. Can we consolidate these instead of having TDX and SME poke at them individually?
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