Re: [PATCH v9 2/4] arm: ARMv7 dirty page logging inital mem region write protect (w/no huge PUD support)

Mario Smarduch
2014-07-25T17:45:21Z

On 07/24/2014 11:16 PM, Alexander Graf wrote:
>
> On 25.07.14 02:56, Mario Smarduch wrote:
>> Patch adds support for initial write protection VM memlsot. This
>> patch series
>> assumes that huge PUDs will not be used in 2nd stage tables.
>
> Is this a valid assumption?

Right now it's unclear if PUDs will be used to back guest
memory, assuming so required quite a bit of additional code.
After discussing on mailing list it was recommended to
treat this as BUG_ON case for now.

>
>>
>> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
>> ---
>> arch/arm/include/asm/kvm_host.h | 1 +
>> arch/arm/include/asm/kvm_mmu.h | 20 ++++++
>> arch/arm/include/asm/pgtable-3level.h | 1 +
>> arch/arm/kvm/arm.c | 9 +++
>> arch/arm/kvm/mmu.c | 128
>> +++++++++++++++++++++++++++++++++
>> 5 files changed, 159 insertions(+)
>>
>> diff --git a/arch/arm/include/asm/kvm_host.h
>> b/arch/arm/include/asm/kvm_host.h
>> index 042206f..6521a2d 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -231,5 +231,6 @@ int kvm_perf_teardown(void);
>> u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
>> int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
>> void kvm_arch_flush_remote_tlbs(struct kvm *);
>> +void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
>> #endif /* __ARM_KVM_HOST_H__ */
>> diff --git a/arch/arm/include/asm/kvm_mmu.h
>> b/arch/arm/include/asm/kvm_mmu.h
>> index 5cc0b0f..08ab5e8 100644
>> --- a/arch/arm/include/asm/kvm_mmu.h
>> +++ b/arch/arm/include/asm/kvm_mmu.h
>> @@ -114,6 +114,26 @@ static inline void kvm_set_s2pmd_writable(pmd_t
>> *pmd)
>> pmd_val(*pmd) |= L_PMD_S2_RDWR;
>> }
>> +static inline void kvm_set_s2pte_readonly(pte_t *pte)
>> +{
>> + pte_val(*pte) = (pte_val(*pte) & ~L_PTE_S2_RDWR) | L_PTE_S2_RDONLY;
>> +}
>> +
>> +static inline bool kvm_s2pte_readonly(pte_t *pte)
>> +{
>> + return (pte_val(*pte) & L_PTE_S2_RDWR) == L_PTE_S2_RDONLY;
>> +}
>> +
>> +static inline void kvm_set_s2pmd_readonly(pmd_t *pmd)
>> +{
>> + pmd_val(*pmd) = (pmd_val(*pmd) & ~L_PMD_S2_RDWR) | L_PMD_S2_RDONLY;
>> +}
>> +
>> +static inline bool kvm_s2pmd_readonly(pmd_t *pmd)
>> +{
>> + return (pmd_val(*pmd) & L_PMD_S2_RDWR) == L_PMD_S2_RDONLY;
>> +}
>> +
>> /* Open coded p*d_addr_end that can deal with 64bit addresses */
>> #define kvm_pgd_addr_end(addr, end) \
>> ({ u64 __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK; \
>> diff --git a/arch/arm/include/asm/pgtable-3level.h
>> b/arch/arm/include/asm/pgtable-3level.h
>> index 85c60ad..d8bb40b 100644
>> --- a/arch/arm/include/asm/pgtable-3level.h
>> +++ b/arch/arm/include/asm/pgtable-3level.h
>> @@ -129,6 +129,7 @@
>> #define L_PTE_S2_RDONLY (_AT(pteval_t, 1) << 6) /*
>> HAP[1] */
>> #define L_PTE_S2_RDWR (_AT(pteval_t, 3) << 6) /*
>> HAP[2:1] */
>> +#define L_PMD_S2_RDONLY (_AT(pteval_t, 1) << 6) /*
>> HAP[1] */
>> #define L_PMD_S2_RDWR (_AT(pmdval_t, 3) << 6) /*
>> HAP[2:1] */
>> /*
>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>> index 3c82b37..e11c2dd 100644
>> --- a/arch/arm/kvm/arm.c
>> +++ b/arch/arm/kvm/arm.c
>> @@ -242,6 +242,15 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
>> const struct kvm_memory_slot *old,
>> enum kvm_mr_change change)
>> {
>> +#ifdef CONFIG_ARM
>
> Same question on CONFIG_ARM here. Is this the define used to distinguish
> between 32bit and 64bit?

Yes let ARM64 compile. Eventually we'll come back to ARM64 soon, and
these will go.
>
>
> Alex
>