From: Tianyu Lan <ltykernel@gmail.com>
To: konrad.wilk@oracle.com, hch@lst.de, m.szyprowski@samsung.com,
robin.murphy@arm.com
Cc: Tianyu Lan <Tianyu.Lan@microsoft.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
vkuznets@redhat.com, thomas.lendacky@amd.com,
brijesh.singh@amd.com, sunilmut@microsoft.com
Subject: [RFC V2 PATCH 9/12] swiotlb: Add bounce buffer remap address setting function
Date: Tue, 13 Apr 2021 11:22:14 -0400 [thread overview]
Message-ID: <20210413152217.3386288-10-ltykernel@gmail.com> (raw)
In-Reply-To: <20210413152217.3386288-1-ltykernel@gmail.com>
From: Tianyu Lan <Tianyu.Lan@microsoft.com>
For Hyper-V isolation VM with AMD SEV SNP, the bounce buffer(shared memory)
needs to be accessed via extra address space(e.g address above bit39).
Hyper-V code may remap extra address space outside of swiotlb. swiotlb_bounce()
needs to use remap virtual address to copy data from/to bounce buffer. Add
new interface swiotlb_set_bounce_remap() to do that.
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
include/linux/swiotlb.h | 5 +++++
kernel/dma/swiotlb.c | 13 ++++++++++++-
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index d9c9fc9ca5d2..3ccd08116683 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -82,8 +82,13 @@ unsigned int swiotlb_max_segment(void);
size_t swiotlb_max_mapping_size(struct device *dev);
bool is_swiotlb_active(void);
void __init swiotlb_adjust_size(unsigned long new_size);
+void swiotlb_set_bounce_remap(unsigned char *vaddr);
#else
#define swiotlb_force SWIOTLB_NO_FORCE
+static inline void swiotlb_set_bounce_remap(unsigned char *vaddr)
+{
+}
+
static inline bool is_swiotlb_buffer(phys_addr_t paddr)
{
return false;
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 7c42df6e6100..5fd2db6aa149 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -94,6 +94,7 @@ static unsigned int io_tlb_index;
* not be bounced (unless SWIOTLB_FORCE is set).
*/
static unsigned int max_segment;
+static unsigned char *swiotlb_bounce_remap_addr;
/*
* We need to save away the original address corresponding to a mapped entry
@@ -421,6 +422,11 @@ void __init swiotlb_exit(void)
swiotlb_cleanup();
}
+void swiotlb_set_bounce_remap(unsigned char *vaddr)
+{
+ swiotlb_bounce_remap_addr = vaddr;
+}
+
/*
* Bounce: copy the swiotlb buffer from or back to the original dma location
*/
@@ -428,7 +434,12 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir)
{
unsigned long pfn = PFN_DOWN(orig_addr);
- unsigned char *vaddr = phys_to_virt(tlb_addr);
+ unsigned char *vaddr;
+
+ if (swiotlb_bounce_remap_addr)
+ vaddr = swiotlb_bounce_remap_addr + tlb_addr - io_tlb_start;
+ else
+ vaddr = phys_to_virt(tlb_addr);
if (PageHighMem(pfn_to_page(pfn))) {
/* The buffer does not have a mapping. Map it in and copy */
--
2.25.1
next prev parent reply other threads:[~2021-04-13 15:23 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 15:22 [RFC V2 PATCH 00/12] x86/Hyper-V: Add Hyper-V Isolation VM support Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 1/12] x86/HV: Initialize GHCB page in Isolation VM Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 2/12] x86/HV: Initialize shared memory boundary " Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 3/12] x86/Hyper-V: Add new hvcall guest address host visibility support Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 4/12] HV: Add Write/Read MSR registers via ghcb Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 5/12] HV: Add ghcb hvcall support for SNP VM Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 6/12] HV/Vmbus: Add SNP support for VMbus channel initiate message Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 7/12] HV/Vmbus: Initialize VMbus ring buffer for Isolation VM Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 8/12] UIO/Hyper-V: Not load UIO HV driver in the isolation VM Tianyu Lan
2021-04-13 15:59 ` Greg KH
2021-04-13 16:00 ` Greg KH
2021-04-14 15:20 ` Tianyu Lan
2021-04-14 15:36 ` Greg KH
2021-04-13 15:22 ` Tianyu Lan [this message]
2021-04-14 6:43 ` [RFC V2 PATCH 9/12] swiotlb: Add bounce buffer remap address setting function Christoph Hellwig
2021-04-14 14:12 ` Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 10/12] HV/IOMMU: Add Hyper-V dma ops support Tianyu Lan
2021-04-13 15:22 ` [RFC V2 PATCH 11/12] HV/Netvsc: Add Isolation VM support for netvsc driver Tianyu Lan
2021-04-18 9:53 ` Leon Romanovsky
2021-04-13 15:22 ` [RFC V2 PATCH 12/12] HV/Storvsc: Add Isolation VM support for storvsc driver Tianyu Lan
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