From: Roman Kisel <[email protected]> Sent: Monday, July 14, 2025 3:16 PM > > Confidential VMBus is built around using buffers not shared with > the host. > > Support allocating encrypted buffers when requested. > > Signed-off-by: Roman Kisel <[email protected]>
Reviewed-by: Michael Kelley <[email protected]> > --- > drivers/hv/channel.c | 49 +++++++++++++++++++++++---------------- > drivers/hv/hyperv_vmbus.h | 3 ++- > drivers/hv/ring_buffer.c | 5 ++-- > 3 files changed, 34 insertions(+), 23 deletions(-) > > diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c > index 35f26fa1ffe7..051eeba800f2 100644 > --- a/drivers/hv/channel.c > +++ b/drivers/hv/channel.c > @@ -443,20 +443,23 @@ static int __vmbus_establish_gpadl(struct vmbus_channel > *channel, > return ret; > } > > - /* > - * Set the "decrypted" flag to true for the set_memory_decrypted() > - * success case. In the failure case, the encryption state of the > - * memory is unknown. Leave "decrypted" as true to ensure the > - * memory will be leaked instead of going back on the free list. > - */ > - gpadl->decrypted = true; > - ret = set_memory_decrypted((unsigned long)kbuffer, > - PFN_UP(size)); > - if (ret) { > - dev_warn(&channel->device_obj->device, > - "Failed to set host visibility for new GPADL %d.\n", > - ret); > - return ret; > + gpadl->decrypted = !((channel->co_external_memory && type == > HV_GPADL_BUFFER) || > + (channel->co_ring_buffer && type == HV_GPADL_RING)); > + if (gpadl->decrypted) { > + /* > + * The "decrypted" flag being true assumes that > set_memory_decrypted() succeeds. > + * But if it fails, the encryption state of the memory is > unknown. In that case, > + * leave "decrypted" as true to ensure the memory is leaked > instead of going back > + * on the free list. > + */ > + ret = set_memory_decrypted((unsigned long)kbuffer, > + PFN_UP(size)); > + if (ret) { > + dev_warn(&channel->device_obj->device, > + "Failed to set host visibility for new GPADL > %d.\n", > + ret); > + return ret; > + } > } > > init_completion(&msginfo->waitevent); > @@ -544,8 +547,10 @@ static int __vmbus_establish_gpadl(struct vmbus_channel > *channel, > * left as true so the memory is leaked instead of being > * put back on the free list. > */ > - if (!set_memory_encrypted((unsigned long)kbuffer, PFN_UP(size))) > - gpadl->decrypted = false; > + if (gpadl->decrypted) { > + if (!set_memory_encrypted((unsigned long)kbuffer, > PFN_UP(size))) > + gpadl->decrypted = false; > + } > } > > return ret; > @@ -676,12 +681,13 @@ static int __vmbus_open(struct vmbus_channel > *newchannel, > goto error_clean_ring; > > err = hv_ringbuffer_init(&newchannel->outbound, > - page, send_pages, 0); > + page, send_pages, 0, > newchannel->co_ring_buffer); > if (err) > goto error_free_gpadl; > > err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages], > - recv_pages, newchannel->max_pkt_size); > + recv_pages, newchannel->max_pkt_size, > + newchannel->co_ring_buffer); > if (err) > goto error_free_gpadl; > > @@ -862,8 +868,11 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, > struct vmbus_gpadl *gpad > > kfree(info); > > - ret = set_memory_encrypted((unsigned long)gpadl->buffer, > - PFN_UP(gpadl->size)); > + if (gpadl->decrypted) > + ret = set_memory_encrypted((unsigned long)gpadl->buffer, > + PFN_UP(gpadl->size)); > + else > + ret = 0; > if (ret) > pr_warn("Fail to set mem host visibility in GPADL teardown > %d.\n", ret); > > diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h > index 2873703d08a9..beae68a70939 100644 > --- a/drivers/hv/hyperv_vmbus.h > +++ b/drivers/hv/hyperv_vmbus.h > @@ -200,7 +200,8 @@ extern int hv_synic_cleanup(unsigned int cpu); > void hv_ringbuffer_pre_init(struct vmbus_channel *channel); > > int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, > - struct page *pages, u32 pagecnt, u32 max_pkt_size); > + struct page *pages, u32 pagecnt, u32 max_pkt_size, > + bool confidential); > > void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info); > > diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c > index 3c9b02471760..05c2cd42fc75 100644 > --- a/drivers/hv/ring_buffer.c > +++ b/drivers/hv/ring_buffer.c > @@ -183,7 +183,8 @@ void hv_ringbuffer_pre_init(struct vmbus_channel *channel) > > /* Initialize the ring buffer. */ > int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, > - struct page *pages, u32 page_cnt, u32 max_pkt_size) > + struct page *pages, u32 page_cnt, u32 max_pkt_size, > + bool confidential) > { > struct page **pages_wraparound; > int i; > @@ -207,7 +208,7 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info > *ring_info, > > ring_info->ring_buffer = (struct hv_ring_buffer *) > vmap(pages_wraparound, page_cnt * 2 - 1, VM_MAP, > - pgprot_decrypted(PAGE_KERNEL)); > + confidential ? PAGE_KERNEL : > pgprot_decrypted(PAGE_KERNEL)); > > kfree(pages_wraparound); > if (!ring_info->ring_buffer) > -- > 2.43.0
