On 1/18/2022 10:59 PM, Maciej S. Szmigiero wrote:
> On 18.01.2022 16:00, Maciej S. Szmigiero wrote:
>> Hi Nikunj,
>>
>> On 18.01.2022 12:06, Nikunj A Dadhania wrote:
>>> From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
>>>
>>> Pin the memory for the data being passed to launch_update_data()
>>> because it gets encrypted before the guest is first run and must
>>> not be moved which would corrupt it.
>>>
>>> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
>>> [ * Changed hva_to_gva() to take an extra argument and return gpa_t.
>>> * Updated sev_pin_memory_in_mmu() error handling.
>>> * As pinning/unpining pages is handled within MMU, removed
>>> {get,put}_user(). ]
>>> Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxx>
>>> ---
>>> arch/x86/kvm/svm/sev.c | 122 ++++++++++++++++++++++++++++++++++++++++-
>>> 1 file changed, 119 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
>>> index 14aeccfc500b..1ae714e83a3c 100644
>>> --- a/arch/x86/kvm/svm/sev.c
>>> +++ b/arch/x86/kvm/svm/sev.c
>>> @@ -22,6 +22,7 @@
>>> #include <asm/trapnr.h>
>>> #include <asm/fpu/xcr.h>
>>> +#include "mmu.h"
>>> #include "x86.h"
>>> #include "svm.h"
>>> #include "svm_ops.h"
>>> @@ -490,6 +491,110 @@ static unsigned long get_num_contig_pages(unsigned long idx,
>>> return pages;
>>> }
>>> +#define SEV_PFERR_RO (PFERR_USER_MASK)
>>> +#define SEV_PFERR_RW (PFERR_WRITE_MASK | PFERR_USER_MASK)
>>> +
>>> +static struct kvm_memory_slot *hva_to_memslot(struct kvm *kvm,
>>> + unsigned long hva)
>>> +{
>>> + struct kvm_memslots *slots = kvm_memslots(kvm);
>>> + struct kvm_memory_slot *memslot;
>>> + int bkt;
>>> +
>>> + kvm_for_each_memslot(memslot, bkt, slots) {
>>> + if (hva >= memslot->userspace_addr &&
>>> + hva < memslot->userspace_addr +
>>> + (memslot->npages << PAGE_SHIFT))
>>> + return memslot;
>>> + }
>>> +
>>> + return NULL;
>>> +}
>>
>> We have kvm_for_each_memslot_in_hva_range() now, please don't do a linear
>> search through memslots.
>> You might need to move the aforementioned macro from kvm_main.c to some
>> header file, though.
>
> Besides performance considerations I can't see the code here taking into
> account the fact that a hva can map to multiple memslots (they an overlap
> in the host address space).
You are right I was returning at the first match, looks like if I switch to using
kvm_for_each_memslot_in_hva_range() it should take care of overlapping hva,
is this understanding correct ?
Regards
Nikunj
