From: Eric van Tassell <evantass@amd.com>
To: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux.dev
Subject: Re: [PATCH 4/4] iommu/amd: Force SNP-enabled VFIO domain to 4K page size
Date: Tue, 17 Jan 2023 07:10:50 -0600 [thread overview]
Message-ID: <209a6ebd-b83c-d1c7-7e36-c109b09779f3@amd.com> (raw)
In-Reply-To: <20230110143137.54517-5-suravee.suthikulpanit@amd.com>
On 1/10/23 08:31, Suravee Suthikulpanit wrote:
> SNP only supports 2M and 4K page sizes. Other page sizes requires
> page smashing to supported sizes. For SNP-enabled guests
> with pass-through devices (via VFIO), it also requires RMP and IOMMU
> page sizes to match.
>
> To simplify the support, for SNP-enabled guest, SNP will smash guest pages
> to 4K page size only, and IOMMU driver will setup the IOMMU v1 page table
> for the VFIO domain of the guest to match the 4K page size.
>
> Co-developed-by: Vasant Hegde <vasant.hegde@amd.com>
> Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> ---
> drivers/iommu/amd/amd_iommu_types.h | 2 ++
> drivers/iommu/amd/iommu.c | 28 ++++++++++++++++++++++++++++
> 2 files changed, 30 insertions(+)
>
> diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
> index ad124959a26a..5249ac18ce6e 100644
> --- a/drivers/iommu/amd/amd_iommu_types.h
> +++ b/drivers/iommu/amd/amd_iommu_types.h
> @@ -279,6 +279,7 @@
> #define AMD_IOMMU_PGSIZES ((~0xFFFUL) & ~(2ULL << 38))
> /* 4K, 2MB, 1G page sizes are supported */
> #define AMD_IOMMU_PGSIZES_V2 (PAGE_SIZE | (1ULL << 21) | (1ULL << 30))
> +#define AMD_IOMMU_PGSIZES_4K (PAGE_SIZE)
>
> /* Bit value definition for dte irq remapping fields*/
> #define DTE_IRQ_PHYS_ADDR_MASK (((1ULL << 45)-1) << 6)
> @@ -440,6 +441,7 @@
> #define PD_IOMMUV2_MASK (1UL << 3) /* domain has gcr3 table */
> #define PD_GIOV_MASK (1UL << 4) /* domain enable GIOV support */
> #define PD_VFIO_MASK (1UL << 5) /* domain enable VFIO support */
> +#define PD_SNP_MASK (1UL << 6) /* domain enable SNP support */
>
> extern bool amd_iommu_dump;
> #define DUMP_printk(format, arg...) \
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index a03723930f70..9a1b010a7d00 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -2422,6 +2422,33 @@ static bool amd_iommu_enforce_cache_coherency(struct iommu_domain *domain)
> return true;97921e769dda1
> }
>
> +static void amd_iommu_set_kvm(struct iommu_domain *domain, struct kvm *kvm)
> +{
> + struct protection_domain *pdom = to_pdomain(domain);
> +
> + if (!amd_iommu_snp_en || !amd_iommu_svm_ops ||
> + !pdom || !(pdom->flags & PD_VFIO_MASK))
> + return;
> +
> + /*
> + * The parameter kvm can be NULL when calling from kvm_vfio_group_del()
> + * and kvm_vfio_destroy().
> + */
> + if (!kvm ||
> + !amd_iommu_svm_ops->is_snp_guest ||
> + !amd_iommu_svm_ops->is_snp_guest(kvm))
> + return;
> +
> + /*
> + * VFIO Domain for SNP guest requires IOMMU and RMP page-size to match,
> + * which can only support 4K and 2M. Currently, only support 4K
> + * IOMMU page-size.
> + */
> + pdom->flags |= PD_SNP_MASK;
> + pdom->domain.pgsize_bitmap = AMD_IOMMU_PGSIZES_4K;
> + pr_debug("%s: Force domain %u page size to 4K.\n", __func__, pdom->id);
> +}
> +
In my opinion the name of this function is to generic and doesn't
describe what it does.
I'd prefer something like amd_iommu_set_4k_pgsz()
> const struct iommu_ops amd_iommu_ops = {
> .capable = amd_iommu_capable,
> .domain_alloc = amd_iommu_domain_alloc,
> @@ -2444,6 +2471,7 @@ const struct iommu_ops amd_iommu_ops = {
> .iotlb_sync = amd_iommu_iotlb_sync,
> .free = amd_iommu_domain_free,
> .enforce_cache_coherency = amd_iommu_enforce_cache_coherency,
> + .set_kvm = amd_iommu_set_kvm,
> }
> };
>
next prev parent reply other threads:[~2023-01-17 13:11 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-10 14:31 [PATCH 0/4] iommu/amd: Force SNP-enabled VFIO domain to 4K page size Suravee Suthikulpanit
2023-01-10 14:31 ` [PATCH 1/4] iommu/amd: Introduce Protection-domain flag VFIO Suravee Suthikulpanit
2023-01-11 3:31 ` kernel test robot
2023-01-13 15:33 ` Jason Gunthorpe
2023-01-19 8:54 ` Kalra, Ashish
2023-01-19 17:44 ` Jason Gunthorpe
2023-01-20 15:12 ` Kalra, Ashish
2023-01-20 16:13 ` Jason Gunthorpe
2023-01-20 17:01 ` Kalra, Ashish
2023-01-20 17:50 ` Jason Gunthorpe
2023-01-20 19:55 ` Kalra, Ashish
2023-01-20 22:42 ` Tom Lendacky
2023-01-21 0:09 ` Jason Gunthorpe
2023-01-10 14:31 ` [PATCH 2/4] iommu/amd: Introduce structure amd_iommu_svm_ops.is_snp_guest() Suravee Suthikulpanit
2023-01-10 14:31 ` [PATCH 3/4] iommu: Introduce IOMMU call-back for processing struct KVM assigned to VFIO Suravee Suthikulpanit
2023-01-10 15:11 ` Robin Murphy
2023-01-17 4:20 ` Suthikulpanit, Suravee
2023-01-17 12:51 ` Robin Murphy
2023-01-13 15:35 ` Jason Gunthorpe
2023-01-17 5:31 ` Suthikulpanit, Suravee
2023-01-17 14:19 ` Jason Gunthorpe
2023-01-10 14:31 ` [PATCH 4/4] iommu/amd: Force SNP-enabled VFIO domain to 4K page size Suravee Suthikulpanit
2023-01-17 13:10 ` Eric van Tassell [this message]
2023-01-16 13:17 ` [PATCH 0/4] " Eric van Tassell
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=209a6ebd-b83c-d1c7-7e36-c109b09779f3@amd.com \
--to=evantass@amd.com \
--cc=iommu@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=suravee.suthikulpanit@amd.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).