On 8/17/2017 10:29 PM, Paolo Bonzini wrote:
On 17/08/2017 13:53, Yu Zhang wrote:
On 8/17/2017 7:57 PM, Paolo Bonzini wrote:
On 12/08/2017 15:35, Yu Zhang wrote:
index a98b88a..50107ae 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -694,7 +694,7 @@ static __always_inline int __linearize(struct
x86_emulate_ctxt *ctxt,
switch (mode) {
case X86EMUL_MODE_PROT64:
*linear = la;
- if (is_noncanonical_address(la))
+ if (emul_is_noncanonical_address(la, ctxt))
goto bad;
*max_size = min_t(u64, ~0u, (1ull << 48) - la);
Oops, you missed one here. Probably best to use ctxt_virt_addr_bits and
then "inline" emul_is_noncanonical_address as "get_canonical(la,
va_bits) != la".
Sorry, I just sent out the v2 patch set without noticing this reply. :-)
The emul_is_noncanonical() is defined in x86.h so that no
ctxt_virt_addr_bits needed in emulate.c, are you
suggesting to use ctx_virt_addr_bits in this file each time before
emul_is_noncanonical_address() is called?
No, only in this instance which uses "48" after the call to
emul_is_noncanonical_address.
Sorry, Paolo. I still do not quite get it.
Do you mean the
*max_size = min_t(u64, ~0u, (1ull << 48) - la);
also need to be changed?
But I do not understand why this statement is used like this. My
understanding is that
for 64 bit scenario, the *max_size is calculated to guarantee la +
*max_size still falls in
the canonical address space.
And if above understanding is correct, I think it should be something
like below:
*max_size = min_t(u64, ~0u - la, (1ull << 48) - la);
And with LA57, may better be changed to:
*max_size = min_t(u64, ~0u - la, (1ull << ctxt_virt_addr_bits(ctxt))
- la);
And for the above
if (emul_is_noncanonical_address(la, ctxt))
we may just leave it as it is.
Is this understanding correct? Or did I misunderstand your comments? :-)
Thanks
Yu
Paolo
