From: Alex Williamson <alex.williamson@redhat.com>
To: Keqian Zhu <zhukeqian1@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
jiangkunkun@huawei.com, kvm@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Kirti Wankhede <kwankhede@nvidia.com>,
Will Deacon <will@kernel.org>,
kvmarm@lists.cs.columbia.edu, Marc Zyngier <maz@kernel.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
wanghaibin.wang@huawei.com,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Alexios Zavras <alexios.zavras@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
Cornelia Huck <cohuck@redhat.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
James Morse <james.morse@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH 4/5] vfio/iommu_type1: Carefully use unmap_unpin_all during dirty tracking
Date: Mon, 11 Jan 2021 14:49:13 -0700 [thread overview]
Message-ID: <20210111144913.3092b1b1@omen.home.shazbot.org> (raw)
In-Reply-To: <20210107092901.19712-5-zhukeqian1@huawei.com>
On Thu, 7 Jan 2021 17:29:00 +0800
Keqian Zhu <zhukeqian1@huawei.com> wrote:
> If we detach group during dirty page tracking, we shouldn't remove
> vfio_dma, because dirty log will lose.
>
> But we don't prevent unmap_unpin_all in vfio_iommu_release, because
> under normal procedure, dirty tracking has been stopped.
This looks like it's creating a larger problem than it's fixing, it's
not our job to maintain the dirty bitmap regardless of what the user
does. If the user detaches the last group in a container causing the
mappings within that container to be deconstructed before the user has
collected dirty pages, that sounds like a user error. A container with
no groups is de-privileged and therefore loses all state. Thanks,
Alex
> Fixes: d6a4c185660c ("vfio iommu: Implementation of ioctl for dirty pages tracking")
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> ---
> drivers/vfio/vfio_iommu_type1.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 26b7eb2a5cfc..9776a059904d 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -2373,7 +2373,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
> if (list_empty(&iommu->external_domain->group_list)) {
> vfio_sanity_check_pfn_list(iommu);
>
> - if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
> + /*
> + * During dirty page tracking, we can't remove
> + * vfio_dma because dirty log will lose.
> + */
> + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) &&
> + !iommu->dirty_page_tracking)
> vfio_iommu_unmap_unpin_all(iommu);
>
> kfree(iommu->external_domain);
> @@ -2406,10 +2411,15 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
> * iommu and external domain doesn't exist, then all the
> * mappings go away too. If it's the last domain with iommu and
> * external domain exist, update accounting
> + *
> + * Note: During dirty page tracking, we can't remove vfio_dma
> + * because dirty log will lose. Just update accounting is a good
> + * choice.
> */
> if (list_empty(&domain->group_list)) {
> if (list_is_singular(&iommu->domain_list)) {
> - if (!iommu->external_domain)
> + if (!iommu->external_domain &&
> + !iommu->dirty_page_tracking)
> vfio_iommu_unmap_unpin_all(iommu);
> else
> vfio_iommu_unmap_unpin_reaccount(iommu);
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: Alex Williamson <alex.williamson@redhat.com>
To: Keqian Zhu <zhukeqian1@huawei.com>
Cc: kvm@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
Kirti Wankhede <kwankhede@nvidia.com>,
Will Deacon <will@kernel.org>,
kvmarm@lists.cs.columbia.edu, Marc Zyngier <maz@kernel.org>,
Joerg Roedel <joro@8bytes.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Alexios Zavras <alexios.zavras@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
Cornelia Huck <cohuck@redhat.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Andrew Morton <akpm@linux-foundation.org>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH 4/5] vfio/iommu_type1: Carefully use unmap_unpin_all during dirty tracking
Date: Mon, 11 Jan 2021 14:49:13 -0700 [thread overview]
Message-ID: <20210111144913.3092b1b1@omen.home.shazbot.org> (raw)
In-Reply-To: <20210107092901.19712-5-zhukeqian1@huawei.com>
On Thu, 7 Jan 2021 17:29:00 +0800
Keqian Zhu <zhukeqian1@huawei.com> wrote:
> If we detach group during dirty page tracking, we shouldn't remove
> vfio_dma, because dirty log will lose.
>
> But we don't prevent unmap_unpin_all in vfio_iommu_release, because
> under normal procedure, dirty tracking has been stopped.
This looks like it's creating a larger problem than it's fixing, it's
not our job to maintain the dirty bitmap regardless of what the user
does. If the user detaches the last group in a container causing the
mappings within that container to be deconstructed before the user has
collected dirty pages, that sounds like a user error. A container with
no groups is de-privileged and therefore loses all state. Thanks,
Alex
> Fixes: d6a4c185660c ("vfio iommu: Implementation of ioctl for dirty pages tracking")
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> ---
> drivers/vfio/vfio_iommu_type1.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 26b7eb2a5cfc..9776a059904d 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -2373,7 +2373,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
> if (list_empty(&iommu->external_domain->group_list)) {
> vfio_sanity_check_pfn_list(iommu);
>
> - if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
> + /*
> + * During dirty page tracking, we can't remove
> + * vfio_dma because dirty log will lose.
> + */
> + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) &&
> + !iommu->dirty_page_tracking)
> vfio_iommu_unmap_unpin_all(iommu);
>
> kfree(iommu->external_domain);
> @@ -2406,10 +2411,15 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
> * iommu and external domain doesn't exist, then all the
> * mappings go away too. If it's the last domain with iommu and
> * external domain exist, update accounting
> + *
> + * Note: During dirty page tracking, we can't remove vfio_dma
> + * because dirty log will lose. Just update accounting is a good
> + * choice.
> */
> if (list_empty(&domain->group_list)) {
> if (list_is_singular(&iommu->domain_list)) {
> - if (!iommu->external_domain)
> + if (!iommu->external_domain &&
> + !iommu->dirty_page_tracking)
> vfio_iommu_unmap_unpin_all(iommu);
> else
> vfio_iommu_unmap_unpin_reaccount(iommu);
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
WARNING: multiple messages have this Message-ID (diff)
From: Alex Williamson <alex.williamson@redhat.com>
To: Keqian Zhu <zhukeqian1@huawei.com>
Cc: <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<iommu@lists.linux-foundation.org>, <kvm@vger.kernel.org>,
<kvmarm@lists.cs.columbia.edu>,
Kirti Wankhede <kwankhede@nvidia.com>,
Cornelia Huck <cohuck@redhat.com>, Will Deacon <will@kernel.org>,
Marc Zyngier <maz@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
James Morse <james.morse@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>,
"Daniel Lezcano" <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Alexios Zavras <alexios.zavras@intel.com>,
<wanghaibin.wang@huawei.com>, <jiangkunkun@huawei.com>
Subject: Re: [PATCH 4/5] vfio/iommu_type1: Carefully use unmap_unpin_all during dirty tracking
Date: Mon, 11 Jan 2021 14:49:13 -0700 [thread overview]
Message-ID: <20210111144913.3092b1b1@omen.home.shazbot.org> (raw)
In-Reply-To: <20210107092901.19712-5-zhukeqian1@huawei.com>
On Thu, 7 Jan 2021 17:29:00 +0800
Keqian Zhu <zhukeqian1@huawei.com> wrote:
> If we detach group during dirty page tracking, we shouldn't remove
> vfio_dma, because dirty log will lose.
>
> But we don't prevent unmap_unpin_all in vfio_iommu_release, because
> under normal procedure, dirty tracking has been stopped.
This looks like it's creating a larger problem than it's fixing, it's
not our job to maintain the dirty bitmap regardless of what the user
does. If the user detaches the last group in a container causing the
mappings within that container to be deconstructed before the user has
collected dirty pages, that sounds like a user error. A container with
no groups is de-privileged and therefore loses all state. Thanks,
Alex
> Fixes: d6a4c185660c ("vfio iommu: Implementation of ioctl for dirty pages tracking")
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> ---
> drivers/vfio/vfio_iommu_type1.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 26b7eb2a5cfc..9776a059904d 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -2373,7 +2373,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
> if (list_empty(&iommu->external_domain->group_list)) {
> vfio_sanity_check_pfn_list(iommu);
>
> - if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
> + /*
> + * During dirty page tracking, we can't remove
> + * vfio_dma because dirty log will lose.
> + */
> + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) &&
> + !iommu->dirty_page_tracking)
> vfio_iommu_unmap_unpin_all(iommu);
>
> kfree(iommu->external_domain);
> @@ -2406,10 +2411,15 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
> * iommu and external domain doesn't exist, then all the
> * mappings go away too. If it's the last domain with iommu and
> * external domain exist, update accounting
> + *
> + * Note: During dirty page tracking, we can't remove vfio_dma
> + * because dirty log will lose. Just update accounting is a good
> + * choice.
> */
> if (list_empty(&domain->group_list)) {
> if (list_is_singular(&iommu->domain_list)) {
> - if (!iommu->external_domain)
> + if (!iommu->external_domain &&
> + !iommu->dirty_page_tracking)
> vfio_iommu_unmap_unpin_all(iommu);
> else
> vfio_iommu_unmap_unpin_reaccount(iommu);
WARNING: multiple messages have this Message-ID (diff)
From: Alex Williamson <alex.williamson@redhat.com>
To: Keqian Zhu <zhukeqian1@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
jiangkunkun@huawei.com, kvm@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Kirti Wankhede <kwankhede@nvidia.com>,
Will Deacon <will@kernel.org>,
kvmarm@lists.cs.columbia.edu, Marc Zyngier <maz@kernel.org>,
Joerg Roedel <joro@8bytes.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
wanghaibin.wang@huawei.com,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Alexios Zavras <alexios.zavras@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
Cornelia Huck <cohuck@redhat.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
James Morse <james.morse@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH 4/5] vfio/iommu_type1: Carefully use unmap_unpin_all during dirty tracking
Date: Mon, 11 Jan 2021 14:49:13 -0700 [thread overview]
Message-ID: <20210111144913.3092b1b1@omen.home.shazbot.org> (raw)
In-Reply-To: <20210107092901.19712-5-zhukeqian1@huawei.com>
On Thu, 7 Jan 2021 17:29:00 +0800
Keqian Zhu <zhukeqian1@huawei.com> wrote:
> If we detach group during dirty page tracking, we shouldn't remove
> vfio_dma, because dirty log will lose.
>
> But we don't prevent unmap_unpin_all in vfio_iommu_release, because
> under normal procedure, dirty tracking has been stopped.
This looks like it's creating a larger problem than it's fixing, it's
not our job to maintain the dirty bitmap regardless of what the user
does. If the user detaches the last group in a container causing the
mappings within that container to be deconstructed before the user has
collected dirty pages, that sounds like a user error. A container with
no groups is de-privileged and therefore loses all state. Thanks,
Alex
> Fixes: d6a4c185660c ("vfio iommu: Implementation of ioctl for dirty pages tracking")
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> ---
> drivers/vfio/vfio_iommu_type1.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 26b7eb2a5cfc..9776a059904d 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -2373,7 +2373,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
> if (list_empty(&iommu->external_domain->group_list)) {
> vfio_sanity_check_pfn_list(iommu);
>
> - if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
> + /*
> + * During dirty page tracking, we can't remove
> + * vfio_dma because dirty log will lose.
> + */
> + if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) &&
> + !iommu->dirty_page_tracking)
> vfio_iommu_unmap_unpin_all(iommu);
>
> kfree(iommu->external_domain);
> @@ -2406,10 +2411,15 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
> * iommu and external domain doesn't exist, then all the
> * mappings go away too. If it's the last domain with iommu and
> * external domain exist, update accounting
> + *
> + * Note: During dirty page tracking, we can't remove vfio_dma
> + * because dirty log will lose. Just update accounting is a good
> + * choice.
> */
> if (list_empty(&domain->group_list)) {
> if (list_is_singular(&iommu->domain_list)) {
> - if (!iommu->external_domain)
> + if (!iommu->external_domain &&
> + !iommu->dirty_page_tracking)
> vfio_iommu_unmap_unpin_all(iommu);
> else
> vfio_iommu_unmap_unpin_reaccount(iommu);
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-01-11 21:49 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 9:28 [PATCH 0/5] vfio/iommu_type1: Some fixes about dirty tracking Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` [PATCH 1/5] vfio/iommu_type1: Fixes vfio_dma_populate_bitmap to avoid dirty lose Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-12 21:20 ` Alex Williamson
2021-01-12 21:20 ` Alex Williamson
2021-01-12 21:20 ` Alex Williamson
2021-01-12 21:20 ` Alex Williamson
2021-01-13 12:35 ` Kirti Wankhede
2021-01-13 12:35 ` Kirti Wankhede
2021-01-13 12:35 ` Kirti Wankhede
2021-01-13 12:35 ` Kirti Wankhede
2021-01-13 15:13 ` Alex Williamson
2021-01-13 15:13 ` Alex Williamson
2021-01-13 15:13 ` Alex Williamson
2021-01-13 15:13 ` Alex Williamson
2021-01-14 13:05 ` Keqian Zhu
2021-01-14 13:05 ` Keqian Zhu
2021-01-14 13:05 ` Keqian Zhu
2021-01-14 13:05 ` Keqian Zhu
2021-01-14 17:14 ` Alex Williamson
2021-01-14 17:14 ` Alex Williamson
2021-01-14 17:14 ` Alex Williamson
2021-01-14 17:14 ` Alex Williamson
2021-01-15 9:41 ` Keqian Zhu
2021-01-15 9:41 ` Keqian Zhu
2021-01-15 9:41 ` Keqian Zhu
2021-01-15 9:41 ` Keqian Zhu
2021-01-07 9:28 ` [PATCH 2/5] vfio/iommu_type1: Populate dirty bitmap for new vfio_dma Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` [PATCH 3/5] vfio/iommu_type1: Populate dirty bitmap when attach group Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:28 ` Keqian Zhu
2021-01-07 9:29 ` [PATCH 4/5] vfio/iommu_type1: Carefully use unmap_unpin_all during dirty tracking Keqian Zhu
2021-01-07 9:29 ` Keqian Zhu
2021-01-07 9:29 ` Keqian Zhu
2021-01-07 9:29 ` Keqian Zhu
2021-01-11 21:49 ` Alex Williamson [this message]
2021-01-11 21:49 ` Alex Williamson
2021-01-11 21:49 ` Alex Williamson
2021-01-11 21:49 ` Alex Williamson
2021-01-12 12:04 ` Keqian Zhu
2021-01-12 12:04 ` Keqian Zhu
2021-01-12 12:04 ` Keqian Zhu
2021-01-12 12:04 ` Keqian Zhu
2021-01-12 19:53 ` Alex Williamson
2021-01-12 19:53 ` Alex Williamson
2021-01-12 19:53 ` Alex Williamson
2021-01-12 19:53 ` Alex Williamson
2021-01-14 12:11 ` Keqian Zhu
2021-01-14 12:11 ` Keqian Zhu
2021-01-14 12:11 ` Keqian Zhu
2021-01-14 12:11 ` Keqian Zhu
2021-01-07 9:29 ` [PATCH 5/5] vfio/iommu_type1: Move sanity_check_pfn_list to unmap_unpin_all Keqian Zhu
2021-01-07 9:29 ` Keqian Zhu
2021-01-07 9:29 ` Keqian Zhu
2021-01-07 9:29 ` Keqian Zhu
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