On 05/03/21 19:22, Sean Christopherson wrote:
On Fri, Mar 05, 2021, Paolo Bonzini wrote:
On 05/03/21 02:10, Sean Christopherson wrote:
Use '0' to denote an invalid pae_root instead of '0' or INVALID_PAGE.
Unlike root_hpa, the pae_roots hold permission bits and thus are
guaranteed to be non-zero. Having to deal with both values leads to
bugs, e.g. failing to set back to INVALID_PAGE, warning on the wrong
value, etc...
I don't dispute this is a good idea, but it deserves one or more comments.
Agreed. What about adding macros?
/* Comment goes here. */
#define INVALID_PAE_ROOT 0
#define IS_VALID_PAE_ROOT(x) (!!(x))
Yep, that's a nice solution.
Paolo
Also, I missed this pattern in mmu_audit.c's mmu_spte_walk():
for (i = 0; i < 4; ++i) {
hpa_t root = vcpu->arch.mmu->pae_root[i];
if (root && VALID_PAGE(root)) {
root &= PT64_BASE_ADDR_MASK;
sp = to_shadow_page(root);
__mmu_spte_walk(vcpu, sp, fn, 2);
}
}