From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v6 18/24] KVM: arm64: vgic-its: Add infrastructure for table lookup Date: Fri, 5 May 2017 05:16:36 -0700 Message-ID: <20170505121636.GF1419@lvm> References: <1493898284-29504-1-git-send-email-eric.auger@redhat.com> <1493898284-29504-19-git-send-email-eric.auger@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: eric.auger.pro@gmail.com, marc.zyngier@arm.com, andre.przywara@arm.com, vijayak@caviumnetworks.com, Vijaya.Kumar@cavium.com, peter.maydell@linaro.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Prasun.Kapoor@cavium.com, drjones@redhat.com, pbonzini@redhat.com, dgilbert@redhat.com, quintela@redhat.com, bjsprakash.linux@gmail.com To: Eric Auger Return-path: Received: from mail-lf0-f46.google.com ([209.85.215.46]:33029 "EHLO mail-lf0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751393AbdEEMQk (ORCPT ); Fri, 5 May 2017 08:16:40 -0400 Received: by mail-lf0-f46.google.com with SMTP id r17so2469053lfg.0 for ; Fri, 05 May 2017 05:16:39 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1493898284-29504-19-git-send-email-eric.auger@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, May 04, 2017 at 01:44:38PM +0200, Eric Auger wrote: > Add a generic scan_its_table() helper whose role consists in > scanning a contiguous table located in guest RAM and applying > a callback on each entry. Entries can be handled as linked lists > since the callback may return an id offset to the next entry and > also indicate whether the entry is the last one. > > Helper functions also are added to compute the device/event ID > offset to the next DTE/ITE. > > compute_next_devid_offset, compute_next_eventid_offset and > scan_table will become static in subsequent patches > > Signed-off-by: Eric Auger > > --- > v5 -> v6: > - add comments about 2d level table scan as suggested by Christoffer > - s/lookup_table/scan_its_table > - scan_table now return 0 if last elt found and +1 if not found > - use int for id > - simplify compute_next_devid/eventid_offset > > v4 -> v5: > - use kvm_read_guest > > v3 -> v4: > - remove static to avoid compilation warning > - correct size computation in looup_table() > - defines now encode the number of bits used for devid and eventid offsets > - use BIT() - 1 to encode the max offets > --- > virt/kvm/arm/vgic/vgic-its.c | 92 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 92 insertions(+) > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index ea8eb6a..1db7e38 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -221,6 +221,8 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id, > > #define VITS_TYPER_IDBITS 16 > #define VITS_TYPER_DEVBITS 16 > +#define VITS_DTE_MAX_DEVID_OFFSET (BIT(14) - 1) > +#define VITS_ITE_MAX_EVENTID_OFFSET (BIT(16) - 1) > > /* > * Finds and returns a collection in the ITS collection table. > @@ -1694,6 +1696,96 @@ int vgic_its_attr_regs_access(struct kvm_device *dev, > return ret; > } > > +u32 compute_next_devid_offset(struct list_head *h, struct its_device *dev) > +{ > + struct its_device *next; > + u32 next_offset; > + > + if (list_is_last(&dev->dev_list, h)) > + return 0; > + next = list_next_entry(dev, dev_list); > + next_offset = next->device_id - dev->device_id; > + > + return min_t(u32, next_offset, VITS_DTE_MAX_DEVID_OFFSET); > +} > + > +u32 compute_next_eventid_offset(struct list_head *h, struct its_ite *ite) > +{ > + struct its_ite *next; > + u32 next_offset; > + > + if (list_is_last(&ite->ite_list, h)) > + return 0; > + next = list_next_entry(ite, ite_list); > + next_offset = next->event_id - ite->event_id; > + > + return min_t(u32, next_offset, VITS_ITE_MAX_EVENTID_OFFSET); > +} > + > +/** > + * entry_fn_t - Callback called on a table entry restore path > + * @its: its handle > + * @id: id of the entry > + * @entry: pointer to the entry > + * @opaque: pointer to an opaque data > + * > + * Return: < 0 on error, 0 if last element was identified, id offset to next > + * element otherwise > + */ > +typedef int (*entry_fn_t)(struct vgic_its *its, u32 id, void *entry, > + void *opaque); > + > +/** > + * scan_its_table - Scan a contiguous table in guest RAM and applies a function > + * to each entry > + * > + * @its: its handle > + * @base: base gpa of the table > + * @size: size of the table in bytes > + * @esz: entry size in bytes > + * @start_id: the ID of the first entry in the table > + * (non zero for 2d level tables) > + * @fn: function to apply on each entry > + * > + * Return: < 0 on error, 0 if last element was identified, 1 otherwise > + * (the last element may not be found on second level tables) > + */ > +int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz, > + int start_id, entry_fn_t fn, void *opaque) > +{ > + void *entry = kzalloc(esz, GFP_KERNEL); > + struct kvm *kvm = its->dev->kvm; > + unsigned long len = size; > + int id = start_id; > + gpa_t gpa = base; > + int ret; > + > + while (len > 0) { > + int next_offset; > + size_t byte_offset; > + > + ret = kvm_read_guest(kvm, gpa, entry, esz); > + if (ret) > + goto out; > + > + next_offset = fn(its, id, entry, opaque); > + if (next_offset <= 0) { > + ret = next_offset; > + goto out; > + } > + > + byte_offset = next_offset * esz; > + id += next_offset; > + gpa += byte_offset; > + len -= byte_offset; > + } > + ret = 1; > + > +out: > + kfree(entry); > + return ret; > +} > + > /** > * vgic_its_save_device_tables - Save the device table and all ITT > * into guest RAM > -- > 2.5.5 > This is much more readable than before. Thanks for making these changes. Reviewed-by: Christoffer Dall From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Fri, 5 May 2017 05:16:36 -0700 Subject: [PATCH v6 18/24] KVM: arm64: vgic-its: Add infrastructure for table lookup In-Reply-To: <1493898284-29504-19-git-send-email-eric.auger@redhat.com> References: <1493898284-29504-1-git-send-email-eric.auger@redhat.com> <1493898284-29504-19-git-send-email-eric.auger@redhat.com> Message-ID: <20170505121636.GF1419@lvm> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, May 04, 2017 at 01:44:38PM +0200, Eric Auger wrote: > Add a generic scan_its_table() helper whose role consists in > scanning a contiguous table located in guest RAM and applying > a callback on each entry. Entries can be handled as linked lists > since the callback may return an id offset to the next entry and > also indicate whether the entry is the last one. > > Helper functions also are added to compute the device/event ID > offset to the next DTE/ITE. > > compute_next_devid_offset, compute_next_eventid_offset and > scan_table will become static in subsequent patches > > Signed-off-by: Eric Auger > > --- > v5 -> v6: > - add comments about 2d level table scan as suggested by Christoffer > - s/lookup_table/scan_its_table > - scan_table now return 0 if last elt found and +1 if not found > - use int for id > - simplify compute_next_devid/eventid_offset > > v4 -> v5: > - use kvm_read_guest > > v3 -> v4: > - remove static to avoid compilation warning > - correct size computation in looup_table() > - defines now encode the number of bits used for devid and eventid offsets > - use BIT() - 1 to encode the max offets > --- > virt/kvm/arm/vgic/vgic-its.c | 92 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 92 insertions(+) > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index ea8eb6a..1db7e38 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -221,6 +221,8 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id, > > #define VITS_TYPER_IDBITS 16 > #define VITS_TYPER_DEVBITS 16 > +#define VITS_DTE_MAX_DEVID_OFFSET (BIT(14) - 1) > +#define VITS_ITE_MAX_EVENTID_OFFSET (BIT(16) - 1) > > /* > * Finds and returns a collection in the ITS collection table. > @@ -1694,6 +1696,96 @@ int vgic_its_attr_regs_access(struct kvm_device *dev, > return ret; > } > > +u32 compute_next_devid_offset(struct list_head *h, struct its_device *dev) > +{ > + struct its_device *next; > + u32 next_offset; > + > + if (list_is_last(&dev->dev_list, h)) > + return 0; > + next = list_next_entry(dev, dev_list); > + next_offset = next->device_id - dev->device_id; > + > + return min_t(u32, next_offset, VITS_DTE_MAX_DEVID_OFFSET); > +} > + > +u32 compute_next_eventid_offset(struct list_head *h, struct its_ite *ite) > +{ > + struct its_ite *next; > + u32 next_offset; > + > + if (list_is_last(&ite->ite_list, h)) > + return 0; > + next = list_next_entry(ite, ite_list); > + next_offset = next->event_id - ite->event_id; > + > + return min_t(u32, next_offset, VITS_ITE_MAX_EVENTID_OFFSET); > +} > + > +/** > + * entry_fn_t - Callback called on a table entry restore path > + * @its: its handle > + * @id: id of the entry > + * @entry: pointer to the entry > + * @opaque: pointer to an opaque data > + * > + * Return: < 0 on error, 0 if last element was identified, id offset to next > + * element otherwise > + */ > +typedef int (*entry_fn_t)(struct vgic_its *its, u32 id, void *entry, > + void *opaque); > + > +/** > + * scan_its_table - Scan a contiguous table in guest RAM and applies a function > + * to each entry > + * > + * @its: its handle > + * @base: base gpa of the table > + * @size: size of the table in bytes > + * @esz: entry size in bytes > + * @start_id: the ID of the first entry in the table > + * (non zero for 2d level tables) > + * @fn: function to apply on each entry > + * > + * Return: < 0 on error, 0 if last element was identified, 1 otherwise > + * (the last element may not be found on second level tables) > + */ > +int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz, > + int start_id, entry_fn_t fn, void *opaque) > +{ > + void *entry = kzalloc(esz, GFP_KERNEL); > + struct kvm *kvm = its->dev->kvm; > + unsigned long len = size; > + int id = start_id; > + gpa_t gpa = base; > + int ret; > + > + while (len > 0) { > + int next_offset; > + size_t byte_offset; > + > + ret = kvm_read_guest(kvm, gpa, entry, esz); > + if (ret) > + goto out; > + > + next_offset = fn(its, id, entry, opaque); > + if (next_offset <= 0) { > + ret = next_offset; > + goto out; > + } > + > + byte_offset = next_offset * esz; > + id += next_offset; > + gpa += byte_offset; > + len -= byte_offset; > + } > + ret = 1; > + > +out: > + kfree(entry); > + return ret; > +} > + > /** > * vgic_its_save_device_tables - Save the device table and all ITT > * into guest RAM > -- > 2.5.5 > This is much more readable than before. Thanks for making these changes. Reviewed-by: Christoffer Dall