Thread (27 messages) 27 messages, 3 authors, 2021-12-10

Re: [PATCH v5 08/12] KVM: Reinstate gfn_to_pfn_cache with invalidation support

From: David Woodhouse <dwmw2@infradead.org>
Date: 2021-12-10 14:59:25
Also in: kvm, kvm-riscv, kvmarm, linux-mips, linux-s390, linuxppc-dev

On Fri, 2021-12-10 at 15:53 +0100, Paolo Bonzini wrote:
On 12/10/21 13:25, David Woodhouse wrote:
quoted
On Thu, 2021-12-09 at 23:34 +0100, Paolo Bonzini wrote:
quoted
Compared to the review it's missing this hunk:
@@ -265,7 +265,7 @@ void kvm_gfn_to_pfn_cache_unmap(struct kvm *kvm, struct gfn_to_pfn_cache *gpc)

         gpc->valid = false;

-       old_khva = gpc->khva;
+       old_khva = (void *)((unsigned long)gpc->khva & ~PAGE_MASK);
         old_dirty = gpc->dirty;
Do you know what? I couldn't bring myself to add that a second time. I
managed it once, but it made me sad.

Did it like this instead:

-       old_khva = gpc->khva;
+       old_khva = gpc->khva - offset_in_page(gpc->khva);
Very nice, and it would have deserved a macro in include/linux if there 
wasn't a decent way to write it.
Indeed. I actually went hunting for such, which is where I found
offset_in_page().

quoted
I checked that for me at least, GCC is clever enough to just do the
mask.

         old_khva = gpc->khva - offset_in_page(gpc->khva);
  131:   48 8b 43 78             mov    0x78(%rbx),%rax
  135:   48 25 00 f0 ff ff       and    $0xfffffffffffff000,%rax


I still don't see the previous patches in kvm/next — is that an
automatic push after testing has passed, or is the kernel.org
infrastructure just *really* slow?
No, it's me really wanting to send out the -rc5 pull request before the 
weekend.  Just wait five more minutes.
Ack. Thanks.
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