[Patch v3 11/14] hv_netvsc: Remove second mapping of send and recv buffers

Michael Kelley
2022-11-16T18:45:40Z

With changes to how Hyper-V guest VMs flip memory between private
(encrypted) and shared (decrypted), creating a second kernel virtual
mapping for shared memory is no longer necessary. Everything needed
for the transition to shared is handled by set_memory_decrypted().

As such, remove the code to create and manage the second
mapping for the pre-allocated send and recv buffers. This mapping
is the last user of hv_map_memory()/hv_unmap_memory(), so delete
these functions as well. Finally, hv_map_memory() is the last
user of vmap_pfn() in Hyper-V guest code, so remove the Kconfig
selection of VMAP_PFN.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
arch/x86/hyperv/ivm.c | 28 ------------------------
drivers/hv/Kconfig | 1 -
drivers/hv/hv_common.c | 11 ----------
drivers/net/hyperv/hyperv_net.h | 2 --
drivers/net/hyperv/netvsc.c | 48 ++---------------------------------------
include/asm-generic/mshyperv.h | 2 --
6 files changed, 2 insertions(+), 90 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 29ccbe8..5e4b8b0 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -349,34 +349,6 @@ void __init hv_vtom_init(void)

#endif /* CONFIG_AMD_MEM_ENCRYPT */

-/*
- * hv_map_memory - map memory to extra space in the AMD SEV-SNP Isolation VM.
- */
-void *hv_map_memory(void *addr, unsigned long size)
-{
- unsigned long *pfns = kcalloc(size / PAGE_SIZE,
- sizeof(unsigned long), GFP_KERNEL);
- void *vaddr;
- int i;
-
- if (!pfns)
- return NULL;
-
- for (i = 0; i < size / PAGE_SIZE; i++)
- pfns[i] = vmalloc_to_pfn(addr + i * PAGE_SIZE) +
- (ms_hyperv.shared_gpa_boundary >> PAGE_SHIFT);
-
- vaddr = vmap_pfn(pfns, size / PAGE_SIZE, pgprot_decrypted(PAGE_KERNEL_NOENC));
- kfree(pfns);
-
- return vaddr;
-}
-
-void hv_unmap_memory(void *addr)
-{
- vunmap(addr);
-}
-
enum hv_isolation_type hv_get_isolation_type(void)
{
if (!(ms_hyperv.priv_high & HV_ISOLATION))
diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 0747a8f..9a074cb 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -8,7 +8,6 @@ config HYPERV
|| (ARM64 && !CPU_BIG_ENDIAN))
select PARAVIRT
select X86_HV_CALLBACK_VECTOR if X86
- select VMAP_PFN
help
Select this option to run Linux as a Hyper-V client operating
system.
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index ae68298..566735f 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -308,14 +308,3 @@ u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_s
return HV_STATUS_INVALID_PARAMETER;
}
EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
-
-void __weak *hv_map_memory(void *addr, unsigned long size)
-{
- return NULL;
-}
-EXPORT_SYMBOL_GPL(hv_map_memory);
-
-void __weak hv_unmap_memory(void *addr)
-{
-}
-EXPORT_SYMBOL_GPL(hv_unmap_memory);
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index dd5919e..33d51e3 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -1139,7 +1139,6 @@ struct netvsc_device {

/* Receive buffer allocated by us but manages by NetVSP */
void *recv_buf;
- void *recv_original_buf;
u32 recv_buf_size; /* allocated bytes */
struct vmbus_gpadl recv_buf_gpadl_handle;
u32 recv_section_cnt;
@@ -1148,7 +1147,6 @@ struct netvsc_device {

/* Send buffer allocated by us */
void *send_buf;
- void *send_original_buf;
u32 send_buf_size;
struct vmbus_gpadl send_buf_gpadl_handle;
u32 send_section_cnt;
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 9352dad..661bbe6 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -154,17 +154,8 @@ static void free_netvsc_device(struct rcu_head *head)
int i;

kfree(nvdev->extension);
-
- if (nvdev->recv_original_buf)
- vfree(nvdev->recv_original_buf);
- else
- vfree(nvdev->recv_buf);
-
- if (nvdev->send_original_buf)
- vfree(nvdev->send_original_buf);
- else
- vfree(nvdev->send_buf);
-
+ vfree(nvdev->recv_buf);
+ vfree(nvdev->send_buf);
bitmap_free(nvdev->send_section_map);

for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
@@ -347,7 +338,6 @@ static int netvsc_init_buf(struct hv_device *device,
struct nvsp_message *init_packet;
unsigned int buf_size;
int i, ret = 0;
- void *vaddr;

/* Get receive buffer area. */
buf_size = device_info->recv_sections * device_info->recv_section_size;
@@ -383,17 +373,6 @@ static int netvsc_init_buf(struct hv_device *device,
goto cleanup;
}

- if (hv_isolation_type_snp()) {
- vaddr = hv_map_memory(net_device->recv_buf, buf_size);
- if (!vaddr) {
- ret = -ENOMEM;
- goto cleanup;
- }
-
- net_device->recv_original_buf = net_device->recv_buf;
- net_device->recv_buf = vaddr;
- }
-
/* Notify the NetVsp of the gpadl handle */
init_packet = &net_device->channel_init_pkt;
memset(init_packet, 0, sizeof(struct nvsp_message));
@@ -497,17 +476,6 @@ static int netvsc_init_buf(struct hv_device *device,
goto cleanup;
}

- if (hv_isolation_type_snp()) {
- vaddr = hv_map_memory(net_device->send_buf, buf_size);
- if (!vaddr) {
- ret = -ENOMEM;
- goto cleanup;
- }
-
- net_device->send_original_buf = net_device->send_buf;
- net_device->send_buf = vaddr;
- }
-
/* Notify the NetVsp of the gpadl handle */
init_packet = &net_device->channel_init_pkt;
memset(init_packet, 0, sizeof(struct nvsp_message));
@@ -762,12 +730,6 @@ void netvsc_device_remove(struct hv_device *device)
netvsc_teardown_send_gpadl(device, net_device, ndev);
}

- if (net_device->recv_original_buf)
- hv_unmap_memory(net_device->recv_buf);
-
- if (net_device->send_original_buf)
- hv_unmap_memory(net_device->send_buf);
-
/* Release all resources */
free_netvsc_device_rcu(net_device);
}
@@ -1831,12 +1793,6 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device,
netif_napi_del(&net_device->chan_table[0].napi);

cleanup2:
- if (net_device->recv_original_buf)
- hv_unmap_memory(net_device->recv_buf);
-
- if (net_device->send_original_buf)
- hv_unmap_memory(net_device->send_buf);
-
free_netvsc_device(&net_device->rcu);

return ERR_PTR(ret);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index bfb9eb9..6fabc4a 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -267,8 +267,6 @@ static inline int cpumask_to_vpset_noself(struct hv_vpset *vpset,
void hyperv_cleanup(void);
bool hv_query_ext_cap(u64 cap_query);
void hv_setup_dma_ops(struct device *dev, bool coherent);
-void *hv_map_memory(void *addr, unsigned long size);
-void hv_unmap_memory(void *addr);
#else /* CONFIG_HYPERV */
static inline bool hv_is_hyperv_initialized(void) { return false; }
static inline bool hv_is_hibernation_supported(void) { return false; }
--
1.8.3.1