On 20/05/2020 08:48, Jan Beulich wrote:
> On 19.05.2020 20:00, Andrew Cooper wrote:
>> On 19/05/2020 17:09, Jan Beulich wrote:
>>> In any event there would be 12 bits to reclaim from the up
>>> pointer - it being a physical address, there'll not be more
>>> than 52 significant bits.
>> Right, but f
On 19.05.2020 20:00, Andrew Cooper wrote:
> On 19/05/2020 17:09, Jan Beulich wrote:
>> In any event there would be 12 bits to reclaim from the up
>> pointer - it being a physical address, there'll not be more
>> than 52 significant bits.
>
> Right, but for L1TF safety, the address bits in the PTE
At 18:09 +0200 on 19 May (1589911795), Jan Beulich wrote:
> static inline int sh_type_has_up_pointer(struct domain *d, unsigned int t)
> {
> /* Multi-page shadows don't have up-pointers */
> if ( t == SH_type_l1_32_shadow
> || t == SH_type_fl1_32_shadow
> || t == SH_type_l
On 19/05/2020 17:09, Jan Beulich wrote:
> On 19.05.2020 17:33, Andrew Cooper wrote:
>> On 19/05/2020 15:48, Jan Beulich wrote:
>>> On 19.05.2020 16:11, Andrew Cooper wrote:
Given that shadow frames are limited to 44 bits anyway (and not yet
levelled safely in the migration stream), my sug
On 19.05.2020 17:33, Andrew Cooper wrote:
> On 19/05/2020 15:48, Jan Beulich wrote:
>> On 19.05.2020 16:11, Andrew Cooper wrote:
>>> Given that shadow frames are limited to 44 bits anyway (and not yet
>>> levelled safely in the migration stream), my suggestion for fixing this
>>> was just to use on
On 19/05/2020 15:55, Jan Beulich wrote:
> On 19.05.2020 16:29, Andrew Cooper wrote:
>> On 19/05/2020 09:14, Jan Beulich wrote:
>>> On 18.05.2020 17:38, Andrew Cooper wrote:
The reserved_bit_page_fault() paths effectively turn reserved bit faults
into
a warning, but in the light of L
On 19/05/2020 15:48, Jan Beulich wrote:
> On 19.05.2020 16:11, Andrew Cooper wrote:
>> On 19/05/2020 09:34, Jan Beulich wrote:
>>> On 18.05.2020 17:38, Andrew Cooper wrote:
@@ -1439,6 +1418,18 @@ void do_page_fault(struct cpu_user_regs *regs)
if ( unlikely(fixup_page_fault(addr, regs
On 19.05.2020 16:29, Andrew Cooper wrote:
> On 19/05/2020 09:14, Jan Beulich wrote:
>> On 18.05.2020 17:38, Andrew Cooper wrote:
>>> The reserved_bit_page_fault() paths effectively turn reserved bit faults
>>> into
>>> a warning, but in the light of L1TF, the real impact is far more serious.
>>>
>
On 19.05.2020 16:11, Andrew Cooper wrote:
> On 19/05/2020 09:34, Jan Beulich wrote:
>> On 18.05.2020 17:38, Andrew Cooper wrote:
>>> @@ -1439,6 +1418,18 @@ void do_page_fault(struct cpu_user_regs *regs)
>>> if ( unlikely(fixup_page_fault(addr, regs) != 0) )
>>> return;
>>>
>>> +
On 19/05/2020 09:14, Jan Beulich wrote:
> On 18.05.2020 17:38, Andrew Cooper wrote:
>> The reserved_bit_page_fault() paths effectively turn reserved bit faults into
>> a warning, but in the light of L1TF, the real impact is far more serious.
>>
>> Xen does not have any reserved bits set in its page
On 19/05/2020 09:34, Jan Beulich wrote:
> On 18.05.2020 17:38, Andrew Cooper wrote:
>> @@ -1439,6 +1418,18 @@ void do_page_fault(struct cpu_user_regs *regs)
>> if ( unlikely(fixup_page_fault(addr, regs) != 0) )
>> return;
>>
>> +/*
>> + * Xen have reserved bits in its pageta
On 18.05.2020 17:38, Andrew Cooper wrote:
> @@ -1439,6 +1418,18 @@ void do_page_fault(struct cpu_user_regs *regs)
> if ( unlikely(fixup_page_fault(addr, regs) != 0) )
> return;
>
> +/*
> + * Xen have reserved bits in its pagetables, nor do we permit PV guests
> to
> + *
On 18.05.2020 17:38, Andrew Cooper wrote:
> The reserved_bit_page_fault() paths effectively turn reserved bit faults into
> a warning, but in the light of L1TF, the real impact is far more serious.
>
> Xen does not have any reserved bits set in its pagetables, nor do we permit PV
> guests to write
On 18/05/2020 16:38, Andrew Cooper wrote:
> The reserved_bit_page_fault() paths effectively turn reserved bit faults into
> a warning, but in the light of L1TF, the real impact is far more serious.
>
> Xen does not have any reserved bits set in its pagetables, nor do we permit PV
> guests to write
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