| Message ID | 20161215055404.29351-6-david@gibson.dropbear.id.au (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 15.12.2016 06:53, David Gibson wrote: > Currently, kvmppc_alloc_hpt() both allocates a new hashed page table (HPT) > and sets it up as the active page table for a VM. For the upcoming HPT > resize implementation we're going to want to allocate HPTs separately from > activating them. > > So, split the allocation itself out into kvmppc_allocate_hpt() and perform > the activation with a new kvmppc_set_hpt() function. Likewise we split > kvmppc_free_hpt(), which just frees the HPT, from kvmppc_release_hpt() > which unsets it as an active HPT, then frees it. > > We also move the logic to fall back to smaller HPT sizes if the first try > fails into the single caller which used that behaviour, > kvmppc_hv_setup_htab_rma(). This introduces a slight semantic change, in > that previously if the initial attempt at CMA allocation failed, we would > fall back to attempting smaller sizes with the page allocator. Now, we > try first CMA, then the page allocator at each size. As far as I can tell > this change should be harmless. > > To match, we make kvmppc_free_hpt() just free the actual HPT itself. The > call to kvmppc_free_lpid() that was there, we move to the single caller. > > Signed-off-by: David Gibson <david@gibson.dropbear.id.au> > --- > arch/powerpc/include/asm/kvm_book3s_64.h | 3 ++ > arch/powerpc/include/asm/kvm_ppc.h | 5 +- > arch/powerpc/kvm/book3s_64_mmu_hv.c | 90 ++++++++++++++++---------------- > arch/powerpc/kvm/book3s_hv.c | 18 +++++-- > 4 files changed, 65 insertions(+), 51 deletions(-) > > diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h > index 8810327..6dc4004 100644 > --- a/arch/powerpc/include/asm/kvm_book3s_64.h > +++ b/arch/powerpc/include/asm/kvm_book3s_64.h > @@ -22,6 +22,9 @@ > > #include <asm/book3s/64/mmu-hash.h> > > +/* Power architecture requires HPT is at least 256kB */ > +#define PPC_MIN_HPT_ORDER 18 > + > #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE > static inline struct kvmppc_book3s_shadow_vcpu *svcpu_get(struct kvm_vcpu *vcpu) > { > diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h > index 3db6be9..41575b8 100644 > --- a/arch/powerpc/include/asm/kvm_ppc.h > +++ b/arch/powerpc/include/asm/kvm_ppc.h > @@ -155,9 +155,10 @@ extern void kvmppc_core_destroy_mmu(struct kvm_vcpu *vcpu); > extern int kvmppc_kvm_pv(struct kvm_vcpu *vcpu); > extern void kvmppc_map_magic(struct kvm_vcpu *vcpu); > > -extern long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp); > +extern int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order); > +extern void kvmppc_set_hpt(struct kvm *kvm, struct kvm_hpt_info *info); > extern long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp); > -extern void kvmppc_free_hpt(struct kvm *kvm); > +extern void kvmppc_free_hpt(struct kvm_hpt_info *info); > extern long kvmppc_prepare_vrma(struct kvm *kvm, > struct kvm_userspace_memory_region *mem); > extern void kvmppc_map_vrma(struct kvm_vcpu *vcpu, > diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c > index fe88132..68bb228 100644 > --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c > +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c > @@ -40,76 +40,70 @@ > > #include "trace_hv.h" > > -/* Power architecture requires HPT is at least 256kB */ > -#define PPC_MIN_HPT_ORDER 18 > - > static long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags, > long pte_index, unsigned long pteh, > unsigned long ptel, unsigned long *pte_idx_ret); > static void kvmppc_rmap_reset(struct kvm *kvm); > > -long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp) > +int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order) > { > unsigned long hpt = 0; > - struct revmap_entry *rev; > + int cma = 0; > struct page *page = NULL; > - long order = KVM_DEFAULT_HPT_ORDER; > - > - if (htab_orderp) { > - order = *htab_orderp; > - if (order < PPC_MIN_HPT_ORDER) > - order = PPC_MIN_HPT_ORDER; > - } Not sure, but as far as I can see, *htab_orderp could still be provided from userspace via kvm_arch_vm_ioctl_hv() -> kvmppc_alloc_reset_hpt() ? In that case, I think you should still check that the order is bigger than PPC_MIN_HPT_ORDER, and return an error code otherwise? Or if you feel confident that this value can never be supplied by userspace anymore, add at least a BUG_ON(order < PPC_MIN_HPT_ORDER) here? > + struct revmap_entry *rev; > + unsigned long npte; > > - kvm->arch.hpt.cma = 0; > + hpt = 0; > + cma = 0; Both hpt and cma are initialized to zero in the variable declarations already, so the above two lines are redundant. > page = kvm_alloc_hpt_cma(1ul << (order - PAGE_SHIFT)); > if (page) { > hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page)); > memset((void *)hpt, 0, (1ul << order)); > - kvm->arch.hpt.cma = 1; > + cma = 1; > } > > - /* Lastly try successively smaller sizes from the page allocator */ > - /* Only do this if userspace didn't specify a size via ioctl */ > - while (!hpt && order > PPC_MIN_HPT_ORDER && !htab_orderp) { > - hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT| > - __GFP_NOWARN, order - PAGE_SHIFT); > - if (!hpt) > - --order; > - } > + if (!hpt) > + hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT > + |__GFP_NOWARN, order - PAGE_SHIFT); > > if (!hpt) > return -ENOMEM; > > - kvm->arch.hpt.virt = hpt; > - kvm->arch.hpt.order = order; > - > - atomic64_set(&kvm->arch.mmio_update, 0); > + /* HPTEs are 2**4 bytes long */ > + npte = 1ul << (order - 4); > > /* Allocate reverse map array */ > - rev = vmalloc(sizeof(struct revmap_entry) * kvmppc_hpt_npte(&kvm->arch.hpt)); > + rev = vmalloc(sizeof(struct revmap_entry) * npte); > if (!rev) { > - pr_err("kvmppc_alloc_hpt: Couldn't alloc reverse map array\n"); > + pr_err("kvmppc_allocate_hpt: Couldn't alloc reverse map array\n"); > goto out_freehpt; So here you jump to out_freehpt before setting info->virt ... > } > - kvm->arch.hpt.rev = rev; > - kvm->arch.sdr1 = __pa(hpt) | (order - 18); > > - pr_info("KVM guest htab at %lx (order %ld), LPID %x\n", > - hpt, order, kvm->arch.lpid); > + info->order = order; > + info->virt = hpt; > + info->cma = cma; > + info->rev = rev; > > - if (htab_orderp) > - *htab_orderp = order; > return 0; > > out_freehpt: > - if (kvm->arch.hpt.cma) > + if (cma) > kvm_free_hpt_cma(page, 1 << (order - PAGE_SHIFT)); > else > - free_pages(hpt, order - PAGE_SHIFT); > + free_pages(info->virt, order - PAGE_SHIFT); ... but here you free info->virt which has not been set in case of the "goto" above. That's clearly wrong. > return -ENOMEM; > } > > +void kvmppc_set_hpt(struct kvm *kvm, struct kvm_hpt_info *info) > +{ > + atomic64_set(&kvm->arch.mmio_update, 0); > + kvm->arch.hpt = *info; > + kvm->arch.sdr1 = __pa(info->virt) | (info->order - 18); > + > + pr_info("KVM guest htab at %lx (order %ld), LPID %x\n", > + info->virt, (long)info->order, kvm->arch.lpid); Not directly related to your patch, but these messages pop up in the dmesg each time I start a guest ... for the normal user who does not have a clue what "htab" means, this can be pretty much annoying. Could you maybe turn this into a pr_debug() instead? > +} > + > long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp) > { > long err = -EBUSY; > @@ -138,24 +132,28 @@ long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp) > *htab_orderp = order; > err = 0; > } else { > - err = kvmppc_alloc_hpt(kvm, htab_orderp); > - order = *htab_orderp; > + struct kvm_hpt_info info; > + > + err = kvmppc_allocate_hpt(&info, *htab_orderp); > + if (err < 0) > + goto out; > + kvmppc_set_hpt(kvm, &info); Just a matter of taste (I dislike gotos if avoidable), but you could also do: err = kvmppc_allocate_hpt(&info, *htab_orderp); if (!err) kvmppc_set_hpt(kvm, &info); ... and that's even one line shorter ;-) > } > out: > mutex_unlock(&kvm->lock); > return err; > } > > -void kvmppc_free_hpt(struct kvm *kvm) > +void kvmppc_free_hpt(struct kvm_hpt_info *info) > { > - kvmppc_free_lpid(kvm->arch.lpid); > - vfree(kvm->arch.hpt.rev); > - if (kvm->arch.hpt.cma) > - kvm_free_hpt_cma(virt_to_page(kvm->arch.hpt.virt), > - 1 << (kvm->arch.hpt.order - PAGE_SHIFT)); > + vfree(info->rev); > + if (info->cma) > + kvm_free_hpt_cma(virt_to_page(info->virt), > + 1 << (info->order - PAGE_SHIFT)); > else > - free_pages(kvm->arch.hpt.virt, > - kvm->arch.hpt.order - PAGE_SHIFT); > + free_pages(info->virt, info->order - PAGE_SHIFT); > + info->virt = 0; > + info->order = 0; > } > > /* Bits in first HPTE dword for pagesize 4k, 64k or 16M */ > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 78baa2b..71c5adb 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -3115,11 +3115,22 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu) > > /* Allocate hashed page table (if not done already) and reset it */ > if (!kvm->arch.hpt.virt) { > - err = kvmppc_alloc_hpt(kvm, NULL); > - if (err) { > + int order = KVM_DEFAULT_HPT_ORDER; > + struct kvm_hpt_info info; > + > + err = kvmppc_allocate_hpt(&info, order); > + /* If we get here, it means userspace didn't specify a > + * size explicitly. So, try successively smaller > + * sizes if the default failed. */ > + while (err < 0 && --order >= PPC_MIN_HPT_ORDER) > + err = kvmppc_allocate_hpt(&info, order); Not sure, but maybe replace "err < 0" with "err == -ENOMEM" in the while condition? Or should it also loop on other future possible errors types? > + if (err < 0) { > pr_err("KVM: Couldn't alloc HPT\n"); > goto out; > } > + > + kvmppc_set_hpt(kvm, &info); > } > > /* Look up the memslot for guest physical address 0 */ > @@ -3357,7 +3368,8 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm) > > kvmppc_free_vcores(kvm); > > - kvmppc_free_hpt(kvm); > + kvmppc_free_lpid(kvm->arch.lpid); > + kvmppc_free_hpt(&kvm->arch.hpt); > > kvmppc_free_pimap(kvm); > } > Thomas -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Dec 16, 2016 at 12:57:26PM +0100, Thomas Huth wrote: > On 15.12.2016 06:53, David Gibson wrote: > > Currently, kvmppc_alloc_hpt() both allocates a new hashed page table (HPT) > > and sets it up as the active page table for a VM. For the upcoming HPT > > resize implementation we're going to want to allocate HPTs separately from > > activating them. > > > > So, split the allocation itself out into kvmppc_allocate_hpt() and perform > > the activation with a new kvmppc_set_hpt() function. Likewise we split > > kvmppc_free_hpt(), which just frees the HPT, from kvmppc_release_hpt() > > which unsets it as an active HPT, then frees it. > > > > We also move the logic to fall back to smaller HPT sizes if the first try > > fails into the single caller which used that behaviour, > > kvmppc_hv_setup_htab_rma(). This introduces a slight semantic change, in > > that previously if the initial attempt at CMA allocation failed, we would > > fall back to attempting smaller sizes with the page allocator. Now, we > > try first CMA, then the page allocator at each size. As far as I can tell > > this change should be harmless. > > > > To match, we make kvmppc_free_hpt() just free the actual HPT itself. The > > call to kvmppc_free_lpid() that was there, we move to the single caller. > > > > Signed-off-by: David Gibson <david@gibson.dropbear.id.au> > > --- > > arch/powerpc/include/asm/kvm_book3s_64.h | 3 ++ > > arch/powerpc/include/asm/kvm_ppc.h | 5 +- > > arch/powerpc/kvm/book3s_64_mmu_hv.c | 90 ++++++++++++++++---------------- > > arch/powerpc/kvm/book3s_hv.c | 18 +++++-- > > 4 files changed, 65 insertions(+), 51 deletions(-) > > > > diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h > > index 8810327..6dc4004 100644 > > --- a/arch/powerpc/include/asm/kvm_book3s_64.h > > +++ b/arch/powerpc/include/asm/kvm_book3s_64.h > > @@ -22,6 +22,9 @@ > > > > #include <asm/book3s/64/mmu-hash.h> > > > > +/* Power architecture requires HPT is at least 256kB */ > > +#define PPC_MIN_HPT_ORDER 18 > > + > > #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE > > static inline struct kvmppc_book3s_shadow_vcpu *svcpu_get(struct kvm_vcpu *vcpu) > > { > > diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h > > index 3db6be9..41575b8 100644 > > --- a/arch/powerpc/include/asm/kvm_ppc.h > > +++ b/arch/powerpc/include/asm/kvm_ppc.h > > @@ -155,9 +155,10 @@ extern void kvmppc_core_destroy_mmu(struct kvm_vcpu *vcpu); > > extern int kvmppc_kvm_pv(struct kvm_vcpu *vcpu); > > extern void kvmppc_map_magic(struct kvm_vcpu *vcpu); > > > > -extern long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp); > > +extern int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order); > > +extern void kvmppc_set_hpt(struct kvm *kvm, struct kvm_hpt_info *info); > > extern long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp); > > -extern void kvmppc_free_hpt(struct kvm *kvm); > > +extern void kvmppc_free_hpt(struct kvm_hpt_info *info); > > extern long kvmppc_prepare_vrma(struct kvm *kvm, > > struct kvm_userspace_memory_region *mem); > > extern void kvmppc_map_vrma(struct kvm_vcpu *vcpu, > > diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c > > index fe88132..68bb228 100644 > > --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c > > +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c > > @@ -40,76 +40,70 @@ > > > > #include "trace_hv.h" > > > > -/* Power architecture requires HPT is at least 256kB */ > > -#define PPC_MIN_HPT_ORDER 18 > > - > > static long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags, > > long pte_index, unsigned long pteh, > > unsigned long ptel, unsigned long *pte_idx_ret); > > static void kvmppc_rmap_reset(struct kvm *kvm); > > > > -long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp) > > +int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order) > > { > > unsigned long hpt = 0; > > - struct revmap_entry *rev; > > + int cma = 0; > > struct page *page = NULL; > > - long order = KVM_DEFAULT_HPT_ORDER; > > - > > - if (htab_orderp) { > > - order = *htab_orderp; > > - if (order < PPC_MIN_HPT_ORDER) > > - order = PPC_MIN_HPT_ORDER; > > - } > > Not sure, but as far as I can see, *htab_orderp could still be provided > from userspace via kvm_arch_vm_ioctl_hv() -> kvmppc_alloc_reset_hpt() ? > In that case, I think you should still check that the order is bigger > than PPC_MIN_HPT_ORDER, and return an error code otherwise? > Or if you feel confident that this value can never be supplied by > userspace anymore, add at least a BUG_ON(order < PPC_MIN_HPT_ORDER) here? Ah, you're right, I do need to check this. > > + struct revmap_entry *rev; > > + unsigned long npte; > > > > - kvm->arch.hpt.cma = 0; > > + hpt = 0; > > + cma = 0; > > Both hpt and cma are initialized to zero in the variable declarations > already, so the above two lines are redundant. Oops. I even spotted that one at some point, then forgot about it again. > > page = kvm_alloc_hpt_cma(1ul << (order - PAGE_SHIFT)); > > if (page) { > > hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page)); > > memset((void *)hpt, 0, (1ul << order)); > > - kvm->arch.hpt.cma = 1; > > + cma = 1; > > } > > > > - /* Lastly try successively smaller sizes from the page allocator */ > > - /* Only do this if userspace didn't specify a size via ioctl */ > > - while (!hpt && order > PPC_MIN_HPT_ORDER && !htab_orderp) { > > - hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT| > > - __GFP_NOWARN, order - PAGE_SHIFT); > > - if (!hpt) > > - --order; > > - } > > + if (!hpt) > > + hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT > > + |__GFP_NOWARN, order - PAGE_SHIFT); > > > > if (!hpt) > > return -ENOMEM; > > > > - kvm->arch.hpt.virt = hpt; > > - kvm->arch.hpt.order = order; > > - > > - atomic64_set(&kvm->arch.mmio_update, 0); > > + /* HPTEs are 2**4 bytes long */ > > + npte = 1ul << (order - 4); > > > > /* Allocate reverse map array */ > > - rev = vmalloc(sizeof(struct revmap_entry) * kvmppc_hpt_npte(&kvm->arch.hpt)); > > + rev = vmalloc(sizeof(struct revmap_entry) * npte); > > if (!rev) { > > - pr_err("kvmppc_alloc_hpt: Couldn't alloc reverse map array\n"); > > + pr_err("kvmppc_allocate_hpt: Couldn't alloc reverse map array\n"); > > goto out_freehpt; > > So here you jump to out_freehpt before setting info->virt ... > > > } > > - kvm->arch.hpt.rev = rev; > > - kvm->arch.sdr1 = __pa(hpt) | (order - 18); > > > > - pr_info("KVM guest htab at %lx (order %ld), LPID %x\n", > > - hpt, order, kvm->arch.lpid); > > + info->order = order; > > + info->virt = hpt; > > + info->cma = cma; > > + info->rev = rev; > > > > - if (htab_orderp) > > - *htab_orderp = order; > > return 0; > > > > out_freehpt: > > - if (kvm->arch.hpt.cma) > > + if (cma) > > kvm_free_hpt_cma(page, 1 << (order - PAGE_SHIFT)); > > else > > - free_pages(hpt, order - PAGE_SHIFT); > > + free_pages(info->virt, order - PAGE_SHIFT); > > ... but here you free info->virt which has not been set in case of the > "goto" above. That's clearly wrong. Good catch. Also, there's only one use of that label, so there's not really any reason to use a goto at all. Adjusted. > > return -ENOMEM; > > } > > > > +void kvmppc_set_hpt(struct kvm *kvm, struct kvm_hpt_info *info) > > +{ > > + atomic64_set(&kvm->arch.mmio_update, 0); > > + kvm->arch.hpt = *info; > > + kvm->arch.sdr1 = __pa(info->virt) | (info->order - 18); > > + > > + pr_info("KVM guest htab at %lx (order %ld), LPID %x\n", > > + info->virt, (long)info->order, kvm->arch.lpid); > > Not directly related to your patch, but these messages pop up in the > dmesg each time I start a guest ... for the normal user who does not > have a clue what "htab" means, this can be pretty much annoying. Could > you maybe turn this into a pr_debug() instead? Maybe, but that's not really in scope for these patches. > > +} > > + > > long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp) > > { > > long err = -EBUSY; > > @@ -138,24 +132,28 @@ long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp) > > *htab_orderp = order; > > err = 0; > > } else { > > - err = kvmppc_alloc_hpt(kvm, htab_orderp); > > - order = *htab_orderp; > > + struct kvm_hpt_info info; > > + > > + err = kvmppc_allocate_hpt(&info, *htab_orderp); > > + if (err < 0) > > + goto out; > > + kvmppc_set_hpt(kvm, &info); > > Just a matter of taste (I dislike gotos if avoidable), but you could > also do: > > err = kvmppc_allocate_hpt(&info, *htab_orderp); > if (!err) > kvmppc_set_hpt(kvm, &info); > > ... and that's even one line shorter ;-) Hrm. I'd prefer to keep the goto: when most 1-line if statements are the exception/failure case, it's very easy to miss that here it's the success case. > > } > > out: > > mutex_unlock(&kvm->lock); > > return err; > > } > > > > -void kvmppc_free_hpt(struct kvm *kvm) > > +void kvmppc_free_hpt(struct kvm_hpt_info *info) > > { > > - kvmppc_free_lpid(kvm->arch.lpid); > > - vfree(kvm->arch.hpt.rev); > > - if (kvm->arch.hpt.cma) > > - kvm_free_hpt_cma(virt_to_page(kvm->arch.hpt.virt), > > - 1 << (kvm->arch.hpt.order - PAGE_SHIFT)); > > + vfree(info->rev); > > + if (info->cma) > > + kvm_free_hpt_cma(virt_to_page(info->virt), > > + 1 << (info->order - PAGE_SHIFT)); > > else > > - free_pages(kvm->arch.hpt.virt, > > - kvm->arch.hpt.order - PAGE_SHIFT); > > + free_pages(info->virt, info->order - PAGE_SHIFT); > > + info->virt = 0; > > + info->order = 0; > > } > > > > /* Bits in first HPTE dword for pagesize 4k, 64k or 16M */ > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > > index 78baa2b..71c5adb 100644 > > --- a/arch/powerpc/kvm/book3s_hv.c > > +++ b/arch/powerpc/kvm/book3s_hv.c > > @@ -3115,11 +3115,22 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu) > > > > /* Allocate hashed page table (if not done already) and reset it */ > > if (!kvm->arch.hpt.virt) { > > - err = kvmppc_alloc_hpt(kvm, NULL); > > - if (err) { > > + int order = KVM_DEFAULT_HPT_ORDER; > > + struct kvm_hpt_info info; > > + > > + err = kvmppc_allocate_hpt(&info, order); > > + /* If we get here, it means userspace didn't specify a > > + * size explicitly. So, try successively smaller > > + * sizes if the default failed. */ > > + while (err < 0 && --order >= PPC_MIN_HPT_ORDER) > > + err = kvmppc_allocate_hpt(&info, order); > > Not sure, but maybe replace "err < 0" with "err == -ENOMEM" in the while > condition? Or should it also loop on other future possible errors types? No, I think you're right. Looping only on -ENOMEM is a better idea. > > + if (err < 0) { > > pr_err("KVM: Couldn't alloc HPT\n"); > > goto out; > > } > > + > > + kvmppc_set_hpt(kvm, &info); > > } > > > > /* Look up the memslot for guest physical address 0 */ > > @@ -3357,7 +3368,8 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm) > > > > kvmppc_free_vcores(kvm); > > > > - kvmppc_free_hpt(kvm); > > + kvmppc_free_lpid(kvm->arch.lpid); > > + kvmppc_free_hpt(&kvm->arch.hpt); > > > > kvmppc_free_pimap(kvm); > > } > > > > Thomas >
diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h index 8810327..6dc4004 100644 --- a/arch/powerpc/include/asm/kvm_book3s_64.h +++ b/arch/powerpc/include/asm/kvm_book3s_64.h @@ -22,6 +22,9 @@ #include <asm/book3s/64/mmu-hash.h> +/* Power architecture requires HPT is at least 256kB */ +#define PPC_MIN_HPT_ORDER 18 + #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE static inline struct kvmppc_book3s_shadow_vcpu *svcpu_get(struct kvm_vcpu *vcpu) { diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index 3db6be9..41575b8 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -155,9 +155,10 @@ extern void kvmppc_core_destroy_mmu(struct kvm_vcpu *vcpu); extern int kvmppc_kvm_pv(struct kvm_vcpu *vcpu); extern void kvmppc_map_magic(struct kvm_vcpu *vcpu); -extern long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp); +extern int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order); +extern void kvmppc_set_hpt(struct kvm *kvm, struct kvm_hpt_info *info); extern long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp); -extern void kvmppc_free_hpt(struct kvm *kvm); +extern void kvmppc_free_hpt(struct kvm_hpt_info *info); extern long kvmppc_prepare_vrma(struct kvm *kvm, struct kvm_userspace_memory_region *mem); extern void kvmppc_map_vrma(struct kvm_vcpu *vcpu, diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index fe88132..68bb228 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -40,76 +40,70 @@ #include "trace_hv.h" -/* Power architecture requires HPT is at least 256kB */ -#define PPC_MIN_HPT_ORDER 18 - static long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags, long pte_index, unsigned long pteh, unsigned long ptel, unsigned long *pte_idx_ret); static void kvmppc_rmap_reset(struct kvm *kvm); -long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp) +int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order) { unsigned long hpt = 0; - struct revmap_entry *rev; + int cma = 0; struct page *page = NULL; - long order = KVM_DEFAULT_HPT_ORDER; - - if (htab_orderp) { - order = *htab_orderp; - if (order < PPC_MIN_HPT_ORDER) - order = PPC_MIN_HPT_ORDER; - } + struct revmap_entry *rev; + unsigned long npte; - kvm->arch.hpt.cma = 0; + hpt = 0; + cma = 0; page = kvm_alloc_hpt_cma(1ul << (order - PAGE_SHIFT)); if (page) { hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page)); memset((void *)hpt, 0, (1ul << order)); - kvm->arch.hpt.cma = 1; + cma = 1; } - /* Lastly try successively smaller sizes from the page allocator */ - /* Only do this if userspace didn't specify a size via ioctl */ - while (!hpt && order > PPC_MIN_HPT_ORDER && !htab_orderp) { - hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT| - __GFP_NOWARN, order - PAGE_SHIFT); - if (!hpt) - --order; - } + if (!hpt) + hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT + |__GFP_NOWARN, order - PAGE_SHIFT); if (!hpt) return -ENOMEM; - kvm->arch.hpt.virt = hpt; - kvm->arch.hpt.order = order; - - atomic64_set(&kvm->arch.mmio_update, 0); + /* HPTEs are 2**4 bytes long */ + npte = 1ul << (order - 4); /* Allocate reverse map array */ - rev = vmalloc(sizeof(struct revmap_entry) * kvmppc_hpt_npte(&kvm->arch.hpt)); + rev = vmalloc(sizeof(struct revmap_entry) * npte); if (!rev) { - pr_err("kvmppc_alloc_hpt: Couldn't alloc reverse map array\n"); + pr_err("kvmppc_allocate_hpt: Couldn't alloc reverse map array\n"); goto out_freehpt; } - kvm->arch.hpt.rev = rev; - kvm->arch.sdr1 = __pa(hpt) | (order - 18); - pr_info("KVM guest htab at %lx (order %ld), LPID %x\n", - hpt, order, kvm->arch.lpid); + info->order = order; + info->virt = hpt; + info->cma = cma; + info->rev = rev; - if (htab_orderp) - *htab_orderp = order; return 0; out_freehpt: - if (kvm->arch.hpt.cma) + if (cma) kvm_free_hpt_cma(page, 1 << (order - PAGE_SHIFT)); else - free_pages(hpt, order - PAGE_SHIFT); + free_pages(info->virt, order - PAGE_SHIFT); return -ENOMEM; } +void kvmppc_set_hpt(struct kvm *kvm, struct kvm_hpt_info *info) +{ + atomic64_set(&kvm->arch.mmio_update, 0); + kvm->arch.hpt = *info; + kvm->arch.sdr1 = __pa(info->virt) | (info->order - 18); + + pr_info("KVM guest htab at %lx (order %ld), LPID %x\n", + info->virt, (long)info->order, kvm->arch.lpid); +} + long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp) { long err = -EBUSY; @@ -138,24 +132,28 @@ long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp) *htab_orderp = order; err = 0; } else { - err = kvmppc_alloc_hpt(kvm, htab_orderp); - order = *htab_orderp; + struct kvm_hpt_info info; + + err = kvmppc_allocate_hpt(&info, *htab_orderp); + if (err < 0) + goto out; + kvmppc_set_hpt(kvm, &info); } out: mutex_unlock(&kvm->lock); return err; } -void kvmppc_free_hpt(struct kvm *kvm) +void kvmppc_free_hpt(struct kvm_hpt_info *info) { - kvmppc_free_lpid(kvm->arch.lpid); - vfree(kvm->arch.hpt.rev); - if (kvm->arch.hpt.cma) - kvm_free_hpt_cma(virt_to_page(kvm->arch.hpt.virt), - 1 << (kvm->arch.hpt.order - PAGE_SHIFT)); + vfree(info->rev); + if (info->cma) + kvm_free_hpt_cma(virt_to_page(info->virt), + 1 << (info->order - PAGE_SHIFT)); else - free_pages(kvm->arch.hpt.virt, - kvm->arch.hpt.order - PAGE_SHIFT); + free_pages(info->virt, info->order - PAGE_SHIFT); + info->virt = 0; + info->order = 0; } /* Bits in first HPTE dword for pagesize 4k, 64k or 16M */ diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 78baa2b..71c5adb 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -3115,11 +3115,22 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu) /* Allocate hashed page table (if not done already) and reset it */ if (!kvm->arch.hpt.virt) { - err = kvmppc_alloc_hpt(kvm, NULL); - if (err) { + int order = KVM_DEFAULT_HPT_ORDER; + struct kvm_hpt_info info; + + err = kvmppc_allocate_hpt(&info, order); + /* If we get here, it means userspace didn't specify a + * size explicitly. So, try successively smaller + * sizes if the default failed. */ + while (err < 0 && --order >= PPC_MIN_HPT_ORDER) + err = kvmppc_allocate_hpt(&info, order); + + if (err < 0) { pr_err("KVM: Couldn't alloc HPT\n"); goto out; } + + kvmppc_set_hpt(kvm, &info); } /* Look up the memslot for guest physical address 0 */ @@ -3357,7 +3368,8 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm) kvmppc_free_vcores(kvm); - kvmppc_free_hpt(kvm); + kvmppc_free_lpid(kvm->arch.lpid); + kvmppc_free_hpt(&kvm->arch.hpt); kvmppc_free_pimap(kvm); }
Currently, kvmppc_alloc_hpt() both allocates a new hashed page table (HPT) and sets it up as the active page table for a VM. For the upcoming HPT resize implementation we're going to want to allocate HPTs separately from activating them. So, split the allocation itself out into kvmppc_allocate_hpt() and perform the activation with a new kvmppc_set_hpt() function. Likewise we split kvmppc_free_hpt(), which just frees the HPT, from kvmppc_release_hpt() which unsets it as an active HPT, then frees it. We also move the logic to fall back to smaller HPT sizes if the first try fails into the single caller which used that behaviour, kvmppc_hv_setup_htab_rma(). This introduces a slight semantic change, in that previously if the initial attempt at CMA allocation failed, we would fall back to attempting smaller sizes with the page allocator. Now, we try first CMA, then the page allocator at each size. As far as I can tell this change should be harmless. To match, we make kvmppc_free_hpt() just free the actual HPT itself. The call to kvmppc_free_lpid() that was there, we move to the single caller. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> --- arch/powerpc/include/asm/kvm_book3s_64.h | 3 ++ arch/powerpc/include/asm/kvm_ppc.h | 5 +- arch/powerpc/kvm/book3s_64_mmu_hv.c | 90 ++++++++++++++++---------------- arch/powerpc/kvm/book3s_hv.c | 18 +++++-- 4 files changed, 65 insertions(+), 51 deletions(-)