[xen staging] x86/AMD: make HT range dynamic for Fam17 and up

[patchbot@xxxxxxx]

commit d6e38eea2d806c53d976603717aebf6e5de30a1e
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Oct 19 10:04:13 2021 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Oct 19 10:04:13 2021 +0200

    x86/AMD: make HT range dynamic for Fam17 and up
    
    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 <igor.druzhinin@xxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/cpu/common.c | 7 +++++++
 xen/arch/x86/dom0_build.c | 7 +++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 302f7f35d8..4a163afbfc 100644
--- 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)))
diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 74b443e509..fe24e11b37 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -524,8 +524,11 @@ int __init dom0_setup_permissions(struct domain *d)
                                          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++ )
--
generated by git-patchbot for /home/xen/git/xen.git#staging