On Fri, Apr 20, 2018 at 03:54:08PM +0100, Punit Agrawal wrote:
> In preparation for creating PUD hugepages at stage 2, add support for
> write protecting PUD hugepages when they are encountered. Write
> protecting guest tables is used to track dirty pages when migrating
> VMs.
>
> Also, provide trivial implementations of required kvm_s2pud_* helpers
> to allow sharing of code with arm32.
>
> Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx>
> Cc: Christoffer Dall <christoffer.dall@xxxxxxx>
> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> ---
> arch/arm/include/asm/kvm_mmu.h | 16 ++++++++++++++++
> arch/arm64/include/asm/kvm_mmu.h | 10 ++++++++++
> virt/kvm/arm/mmu.c | 9 ++++++---
> 3 files changed, 32 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
> index 5907a81ad5c1..224c22c0a69c 100644
> --- a/arch/arm/include/asm/kvm_mmu.h
> +++ b/arch/arm/include/asm/kvm_mmu.h
> @@ -80,6 +80,22 @@ void kvm_clear_hyp_idmap(void);
>
> #define kvm_pmd_mkhuge(pmd) pmd_mkhuge(pmd)
>
> +/*
> + * The following kvm_*pud*() functionas are provided strictly to allow
> + * sharing code with arm64. They should never be called in practice.
> + */
> +static inline void kvm_set_s2pud_readonly(pud_t *pud)
> +{
> + BUG();
> +}
> +
> +static inline bool kvm_s2pud_readonly(pud_t *pud)
> +{
> + BUG();
> + return false;
> +}
> +
> +
> static inline void kvm_set_pmd(pmd_t *pmd, pmd_t new_pmd)
> {
> *pmd = new_pmd;
> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
> index d962508ce4b3..f440cf216a23 100644
> --- a/arch/arm64/include/asm/kvm_mmu.h
> +++ b/arch/arm64/include/asm/kvm_mmu.h
> @@ -240,6 +240,16 @@ static inline bool kvm_s2pmd_exec(pmd_t *pmdp)
> return !(READ_ONCE(pmd_val(*pmdp)) & PMD_S2_XN);
> }
>
> +static inline void kvm_set_s2pud_readonly(pud_t *pudp)
> +{
> + kvm_set_s2pte_readonly((pte_t *)pudp);
> +}
> +
> +static inline bool kvm_s2pud_readonly(pud_t *pudp)
> +{
> + return kvm_s2pte_readonly((pte_t *)pudp);
> +}
> +
> static inline bool kvm_page_empty(void *ptr)
> {
> struct page *ptr_page = virt_to_page(ptr);
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index f72ae7a6dea0..5f53909da90e 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -1286,9 +1286,12 @@ static void stage2_wp_puds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
> do {
> next = stage2_pud_addr_end(addr, end);
> if (!stage2_pud_none(*pud)) {
> - /* TODO:PUD not supported, revisit later if supported */
> - BUG_ON(stage2_pud_huge(*pud));
> - stage2_wp_pmds(pud, addr, next);
> + if (stage2_pud_huge(*pud)) {
> + if (!kvm_s2pud_readonly(pud))
> + kvm_set_s2pud_readonly(pud);
> + } else {
> + stage2_wp_pmds(pud, addr, next);
> + }
> }
> } while (pud++, addr = next, addr != end);
> }
> --
> 2.17.0
>
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxx>
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
