On 6/18/2024 1:55 PM, Binbin Wu wrote:
On 6/6/2024 2:57 AM, Sean Christopherson wrote:
On Mon, Jan 22, 2024, Binbin Wu wrote:
+ if (this_cpu_has(X86_FEATURE_LA57) && read_cr4() & X86_CR4_LA57)
Checking for feature support seems superfluous, e.g. LA57 should
never be set if
it's unsupported. Then you can do
lam_mask = is_la57_enabled() ? LAM57_MASK : LAM48_MASK;
OK, will drop the feature check.
+ lam_mask = LAM57_MASK;
+
+ vaddr = alloc_vpage();
+ install_page(current_page_table(), virt_to_phys(alloc_page()),
vaddr);
+ /*
+ * Since the stack memory address in KUT doesn't follow kernel
address
+ * space partition rule, reuse the memory address for
descriptor and
+ * the target address in the descriptor of invvpid.
+ */
+ operand = (struct invvpid_operand *)vaddr;
Why bother backing the virtual address? MOV needs a valid
translation, but
INVVPID does not (ditto for INVLPG and INVPCID, though it might be
simpler and
easier to just use the allocated address for those).
OK, will remove the unnecessary code.
Sorry, the backing is still needed here.
The target address inside the invvpid descriptor (operand->gla) doesn't
need a valid translation, but the invvpid descriptor itself needs a
valid translation.
+ operand->vpid = 0xffff;
+ operand->gla = (u64)vaddr;
+ operand = (struct invvpid_operand
*)set_la_non_canonical((u64)operand,
+ lam_mask);
+ fault = test_for_exception(GP_VECTOR, ds_invvpid, operand);
+ report(!fault, "INVVPID (LAM on): tagged operand");
