At the time of d838ac2539cf ("x86: don't allow Dom0 access to the HT
address range") documentation correctly stated that the range was
completely fixed. For Fam17 and newer, it lives at the top of physical
address space, though.To correctly determine the top of physical address space, we need to account for their physical address reduction, hence the calculation of paddr_bits also gets adjusted. While for paddr_bits < 40 the HT range is completely hidden, there's no need to suppress the range insertion in that case: It'll just have no real meaning. Reported-by: Igor Druzhinin <[email protected]> Signed-off-by: Jan Beulich <[email protected]> --- v2: Move adjustment last, to leave hap_paddr_bits unaffected. Add comment. --- a/xen/arch/x86/cpu/common.c +++ b/xen/arch/x86/cpu/common.c @@ -349,16 +349,23 @@ void __init early_cpu_init(void) eax = cpuid_eax(0x80000000); if ((eax >> 16) == 0x8000 && eax >= 0x80000008) { + ebx = eax >= 0x8000001f ? cpuid_ebx(0x8000001f) : 0; eax = cpuid_eax(0x80000008); + paddr_bits = eax & 0xff; if (paddr_bits > PADDR_BITS) paddr_bits = PADDR_BITS; + vaddr_bits = (eax >> 8) & 0xff; if (vaddr_bits > VADDR_BITS) vaddr_bits = VADDR_BITS; + hap_paddr_bits = ((eax >> 16) & 0xff) ?: paddr_bits; if (hap_paddr_bits > PADDR_BITS) hap_paddr_bits = PADDR_BITS; + + /* Account for SME's physical address space reduction. */ + paddr_bits -= (ebx >> 6) & 0x3f; } if (!(c->x86_vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON))) --- a/xen/arch/x86/dom0_build.c +++ b/xen/arch/x86/dom0_build.c @@ -524,8 +524,11 @@ int __init dom0_setup_permissions(struct MSI_ADDR_DEST_ID_MASK)); /* HyperTransport range. */ if ( boot_cpu_data.x86_vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON) ) - rc |= iomem_deny_access(d, paddr_to_pfn(0xfdULL << 32), - paddr_to_pfn((1ULL << 40) - 1)); + { + mfn = paddr_to_pfn(1UL << + (boot_cpu_data.x86 < 0x17 ? 40 : paddr_bits)); + rc |= iomem_deny_access(d, mfn - paddr_to_pfn(3UL << 32), mfn - 1); + } /* Remove access to E820_UNUSABLE I/O regions above 1MB. */ for ( i = 0; i < e820.nr_map; i++ )
