On 27/06/18 14:47, Suzuki K Poulose wrote:
> Hi Marc,
>
> On 27/06/18 13:20, Marc Zyngier wrote:
>> The {pmd,pud,pgd}_populate accessors usage in the kernel have always
>> been a bit weird in KVM. We don't have a struct mm to pass (and
>> neither does the kernel most of the time, but still...), and
>> the 32bit code has all kind of cache maintenance that doesn't make
>> sense on ARMv7+ when MP extensions are mandatory (which is the
>> case when the VEs are present).
>>
>> Let's bite the bullet and provide our own implementations. The
>> only bit of architectural code left has to do with building the table
>> entry itself (arm64 having up to 52bit PA, arm lacking PUD level).
>>
>> Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
>> Acked-by: Christoffer Dall <christoffer.dall@xxxxxxx>
>> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
>> ---
>> arch/arm/include/asm/kvm_mmu.h | 4 ++++
>> arch/arm64/include/asm/kvm_mmu.h | 7 +++++++
>> virt/kvm/arm/mmu.c | 8 +++++---
>> 3 files changed, 16 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
>> index b2feaea1434c..265ea9cf7df7 100644
>> --- a/arch/arm/include/asm/kvm_mmu.h
>> +++ b/arch/arm/include/asm/kvm_mmu.h
>> @@ -75,6 +75,10 @@ phys_addr_t kvm_get_idmap_vector(void);
>> int kvm_mmu_init(void);
>> void kvm_clear_hyp_idmap(void);
>>
>> +#define kvm_mk_pmd(ptep) __pmd(__pa(ptep) | PMD_TYPE_TABLE)
>> +#define kvm_mk_pud(pmdp) __pud(__pa(pmdp) | PMD_TYPE_TABLE)
>> +#define kvm_mk_pgd(pudp) ({ BUILD_BUG(); 0; })
>> +
>> static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
>> {
>> pte_val(pte) |= L_PTE_S2_RDWR;
>> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
>> index 25c9a91f6a87..2f05be2bed63 100644
>> --- a/arch/arm64/include/asm/kvm_mmu.h
>> +++ b/arch/arm64/include/asm/kvm_mmu.h
>> @@ -169,6 +169,13 @@ phys_addr_t kvm_get_idmap_vector(void);
>> int kvm_mmu_init(void);
>> void kvm_clear_hyp_idmap(void);
>>
>> +#define kvm_mk_pmd(ptep) \
>> + __pmd(__phys_to_pmd_val(__pa(ptep) | PMD_TYPE_TABLE))
>> +#define kvm_mk_pud(pmdp) \
>> + __pud(__phys_to_pud_val(__pa(pmdp) | PMD_TYPE_TABLE))
>> +#define kvm_mk_pgd(pudp) \
>> + __pgd(__phys_to_pgd_val(__pa(pudp) | PUD_TYPE_TABLE))
>> +
>
> I believe this is wrong, as the __phys_to_p.d_val could strip of the
> TABLE bit. The correct usage is :
>
> __pXd(__phys_to_pXd_val(__pa(ptr)) | PxD_TYPE_TABLE)
Ah, you're absolutely correct! Fixed now.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
