KVM Archive on lore.kernel.org
 help / color / Atom feed
From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: linuxppc-dev@lists.ozlabs.org
Cc: David Gibson <david@gibson.dropbear.id.au>,
	kvm@vger.kernel.org, Alistair Popple <alistair@popple.id.au>,
	Alex Williamson <alex.williamson@redhat.com>,
	Oliver O'Halloran <oohall@gmail.com>,
	Alexey Kardashevskiy <aik@ozlabs.ru>
Subject: [PATCH kernel RFC 4/4] vfio/spapr_tce: Advertise and allow a huge DMA windows at 4GB
Date: Mon,  2 Dec 2019 12:59:53 +1100
Message-ID: <20191202015953.127902-5-aik@ozlabs.ru> (raw)
In-Reply-To: <20191202015953.127902-1-aik@ozlabs.ru>

So far the only option for a big 64big DMA window was a window located
at 0x800.0000.0000.0000 (1<<59) which creates problems for devices
supporting smaller DMA masks.

This exploits a POWER9 PHB option to allow the second DMA window to map
at 0 and advertises it with a 4GB offset to avoid overlap with
the default 32bit window.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---


This is an additional option and not inside
vfio_iommu_spapr_tce_ddw_info as the new option gets
a new flag and one would expect a new member in
vfio_iommu_spapr_tce_info per a flag but can squash it
into vfio_iommu_spapr_tce_ddw_info, should I?


---
 include/uapi/linux/vfio.h           |  2 ++
 drivers/vfio/vfio_iommu_spapr_tce.c | 10 ++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 9e843a147ead..c7f89d47335a 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -831,9 +831,11 @@ struct vfio_iommu_spapr_tce_info {
 	__u32 argsz;
 	__u32 flags;
 #define VFIO_IOMMU_SPAPR_INFO_DDW	(1 << 0)	/* DDW supported */
+#define VFIO_IOMMU_SPAPR_INFO_DDW_START	(1 << 1)	/* DDW offset */
 	__u32 dma32_window_start;	/* 32 bit window start (bytes) */
 	__u32 dma32_window_size;	/* 32 bit window size (bytes) */
 	struct vfio_iommu_spapr_tce_ddw_info ddw;
+	__u64 dma64_window_start;
 };
 
 #define VFIO_IOMMU_SPAPR_TCE_GET_INFO	_IO(VFIO_TYPE, VFIO_BASE + 12)
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 26cef65b41e7..470008c3359f 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -691,7 +691,7 @@ static long tce_iommu_create_window(struct tce_container *container,
 	container->tables[num] = tbl;
 
 	/* Return start address assigned by platform in create_table() */
-	*start_addr = tbl->it_offset << tbl->it_page_shift;
+	*start_addr = tbl->it_dmaoff << tbl->it_page_shift;
 
 	return 0;
 
@@ -842,7 +842,13 @@ static long tce_iommu_ioctl(void *iommu_data,
 			info.ddw.levels = table_group->max_levels;
 		}
 
-		ddwsz = offsetofend(struct vfio_iommu_spapr_tce_info, ddw);
+		ddwsz = offsetofend(struct vfio_iommu_spapr_tce_info,
+				dma64_window_start);
+
+		if (info.argsz >= ddwsz) {
+			info.flags |= VFIO_IOMMU_SPAPR_INFO_DDW_START;
+			info.dma64_window_start = table_group->tce64_start;
+		}
 
 		if (info.argsz >= ddwsz)
 			minsz = ddwsz;
-- 
2.17.1


  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-02  1:59 [PATCH kernel RFC 0/4] powerpc/powenv/ioda: Allow huge DMA window " Alexey Kardashevskiy
2019-12-02  1:59 ` [PATCH kernel RFC 1/4] powerpc/powernv/ioda: Rework for " Alexey Kardashevskiy
2019-12-02  1:59 ` [PATCH kernel RFC 2/4] powerpc/powernv/ioda: Allow smaller TCE table levels Alexey Kardashevskiy
2019-12-02  1:59 ` [PATCH kernel RFC 3/4] powerpc/powernv/phb4: Add 4GB IOMMU bypass mode Alexey Kardashevskiy
2019-12-02  1:59 ` Alexey Kardashevskiy [this message]
2019-12-02  5:36 ` [PATCH kernel RFC 0/4] powerpc/powenv/ioda: Allow huge DMA window at 4GB Alistair Popple
2019-12-02  5:58   ` Alexey Kardashevskiy
2019-12-02  5:51 ` [PATCH kernel RFC 00/4] powerpc/powernv/ioda: Move TCE bypass base to PE Alexey Kardashevskiy
2020-01-10  4:18 ` [PATCH kernel RFC 0/4] powerpc/powenv/ioda: Allow huge DMA window at 4GB Alexey Kardashevskiy
2020-01-23  0:53   ` Alexey Kardashevskiy
2020-01-23  1:17     ` David Gibson
2020-01-23  8:42       ` Alexey Kardashevskiy

Reply instructions:

You may reply publically 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=20191202015953.127902-5-aik@ozlabs.ru \
    --to=aik@ozlabs.ru \
    --cc=alex.williamson@redhat.com \
    --cc=alistair@popple.id.au \
    --cc=david@gibson.dropbear.id.au \
    --cc=kvm@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=oohall@gmail.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

KVM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/kvm/0 kvm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 kvm kvm/ https://lore.kernel.org/kvm \
		kvm@vger.kernel.org
	public-inbox-index kvm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.kvm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git