drivers: hv: Turn off write permission on the hypercall page

[pandora-kernel.git] / drivers / hv / hv.c

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 0fb100e..f5cccd0 100644 (file)
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -158,6 +158,8 @@ int hv_init(void)
        memset(hv_context.synic_event_page, 0, sizeof(void *) * MAX_NUM_CPUS);
        memset(hv_context.synic_message_page, 0,
               sizeof(void *) * MAX_NUM_CPUS);
+       memset(hv_context.post_msg_page, 0,
+              sizeof(void *) * MAX_NUM_CPUS);
 
        if (!query_hypervisor_presence())
                goto cleanup;
@@ -176,7 +178,7 @@ int hv_init(void)
        /* See if the hypercall page is already set */
        rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 
-       virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);
+       virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
 
        if (!virtaddr)
                goto cleanup;
@@ -258,26 +260,18 @@ u16 hv_post_message(union hv_connection_id connection_id,
                  enum hv_message_type message_type,
                  void *payload, size_t payload_size)
 {
-       struct aligned_input {
-               u64 alignment8;
-               struct hv_input_post_message msg;
-       };
 
        struct hv_input_post_message *aligned_msg;
        u16 status;
-       unsigned long addr;
 
        if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
                return -EMSGSIZE;
 
-       addr = (unsigned long)kmalloc(sizeof(struct aligned_input), GFP_ATOMIC);
-       if (!addr)
-               return -ENOMEM;
-
        aligned_msg = (struct hv_input_post_message *)
-                       (ALIGN(addr, HV_HYPERCALL_PARAM_ALIGN));
+                       hv_context.post_msg_page[get_cpu()];
 
        aligned_msg->connectionid = connection_id;
+       aligned_msg->reserved = 0;
        aligned_msg->message_type = message_type;
        aligned_msg->payload_size = payload_size;
        memcpy((void *)aligned_msg->payload, payload, payload_size);
@@ -285,8 +279,7 @@ u16 hv_post_message(union hv_connection_id connection_id,
        status = do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL)
                & 0xFFFF;
 
-       kfree((void *)addr);
-
+       put_cpu();
        return status;
 }
 
@@ -347,6 +340,14 @@ void hv_synic_init(void *irqarg)
                goto cleanup;
        }
 
+       hv_context.post_msg_page[cpu] =
+               (void *)get_zeroed_page(GFP_ATOMIC);
+
+       if (hv_context.post_msg_page[cpu] == NULL) {
+               pr_err("Unable to allocate post msg page\n");
+               goto cleanup;
+       }
+
        /* Setup the Synic's message page */
        rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
        simp.simp_enabled = 1;
@@ -388,6 +389,8 @@ cleanup:
 
        if (hv_context.synic_message_page[cpu])
                free_page((unsigned long)hv_context.synic_message_page[cpu]);
+       if (hv_context.post_msg_page[cpu])
+               free_page((unsigned long)hv_context.post_msg_page[cpu]);
        return;
 }
 
@@ -426,4 +429,5 @@ void hv_synic_cleanup(void *arg)
 
        free_page((unsigned long)hv_context.synic_message_page[cpu]);
        free_page((unsigned long)hv_context.synic_event_page[cpu]);
+       free_page((unsigned long)hv_context.post_msg_page[cpu]);
 }