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iommu/amd: Page-specific invalidations for more than one page

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Currently, IOMMU invalidations and device-IOTLB invalidations using
AMD IOMMU fall back to full address-space invalidation if more than a
single page need to be flushed.

Full flushes are especially inefficient when the IOMMU is virtualized by
a hypervisor, since it requires the hypervisor to synchronize the entire
address-space.

AMD IOMMUs allow to provide a mask to perform page-specific
invalidations for multiple pages that match the address. The mask is
encoded as part of the address, and the first zero bit in the address
(in bits [51:12]) indicates the mask size.

Use this hardware feature to perform selective IOMMU and IOTLB flushes.
Combine the logic between both for better code reuse.

The IOMMU invalidations passed a smoke-test. The device IOTLB
invalidations are untested.

Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
Cc: Jiajun Cao <caojiajun@vmware.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Nadav Amit <namit@vmware.com>
Link: https://lore.kernel.org/r/20210323210619.513069-1-namit@vmware.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Nadav Amit 2021-03-23 14:06:19 -07:00 committed by Joerg Roedel
parent fc1b662050
commit 268aa45482
1 changed files with 48 additions and 40 deletions
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88
drivers/iommu/amd/iommu.c
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@ -852,33 +852,58 @@ static void build_inv_dte(struct iommu_cmd *cmd, u16 devid)
CMD_SET_TYPE(cmd, CMD_INV_DEV_ENTRY);
}
/*
* Builds an invalidation address which is suitable for one page or multiple
* pages. Sets the size bit (S) as needed is more than one page is flushed.
*/
static inline u64 build_inv_address(u64 address, size_t size)
{
u64 pages, end, msb_diff;
pages = iommu_num_pages(address, size, PAGE_SIZE);
if (pages == 1)
return address & PAGE_MASK;
end = address + size - 1;
/*
* msb_diff would hold the index of the most significant bit that
* flipped between the start and end.
*/
msb_diff = fls64(end ^ address) - 1;
/*
* Bits 63:52 are sign extended. If for some reason bit 51 is different
* between the start and the end, invalidate everything.
*/
if (unlikely(msb_diff > 51)) {
address = CMD_INV_IOMMU_ALL_PAGES_ADDRESS;
} else {
/*
* The msb-bit must be clear on the address. Just set all the
* lower bits.
*/
address |= 1ull << (msb_diff - 1);
}
/* Clear bits 11:0 */
address &= PAGE_MASK;
/* Set the size bit - we flush more than one 4kb page */
return address | CMD_INV_IOMMU_PAGES_SIZE_MASK;
}
static void build_inv_iommu_pages(struct iommu_cmd *cmd, u64 address,
size_t size, u16 domid, int pde)
{
u64 pages;
bool s;
pages = iommu_num_pages(address, size, PAGE_SIZE);
s = false;
if (pages > 1) {
/*
* If we have to flush more than one page, flush all
* TLB entries for this domain
*/
address = CMD_INV_IOMMU_ALL_PAGES_ADDRESS;
s = true;
}
address &= PAGE_MASK;
u64 inv_address = build_inv_address(address, size);
memset(cmd, 0, sizeof(*cmd));
cmd->data[1] |= domid;
cmd->data[2] = lower_32_bits(address);
cmd->data[3] = upper_32_bits(address);
cmd->data[2] = lower_32_bits(inv_address);
cmd->data[3] = upper_32_bits(inv_address);
CMD_SET_TYPE(cmd, CMD_INV_IOMMU_PAGES);
if (s) /* size bit - we flush more than one 4kb page */
cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
if (pde) /* PDE bit - we want to flush everything, not only the PTEs */
cmd->data[2] |= CMD_INV_IOMMU_PAGES_PDE_MASK;
}
@ -886,32 +911,15 @@ static void build_inv_iommu_pages(struct iommu_cmd *cmd, u64 address,
static void build_inv_iotlb_pages(struct iommu_cmd *cmd, u16 devid, int qdep,
u64 address, size_t size)
{
u64 pages;
bool s;
pages = iommu_num_pages(address, size, PAGE_SIZE);
s = false;
if (pages > 1) {
/*
* If we have to flush more than one page, flush all
* TLB entries for this domain
*/
address = CMD_INV_IOMMU_ALL_PAGES_ADDRESS;
s = true;
}
address &= PAGE_MASK;
u64 inv_address = build_inv_address(address, size);
memset(cmd, 0, sizeof(*cmd));
cmd->data[0] = devid;
cmd->data[0] |= (qdep & 0xff) << 24;
cmd->data[1] = devid;
cmd->data[2] = lower_32_bits(address);
cmd->data[3] = upper_32_bits(address);
cmd->data[2] = lower_32_bits(inv_address);
cmd->data[3] = upper_32_bits(inv_address);
CMD_SET_TYPE(cmd, CMD_INV_IOTLB_PAGES);
if (s)
cmd->data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
}
static void build_inv_iommu_pasid(struct iommu_cmd *cmd, u16 domid, u32 pasid,