[Xen-devel] [PATCH] vixen: port of shadow PV console's page for L2 DomU

[Sarah Newman <srn@xxxxxxxxx>]

The current version of vixen handles console output from the guest
but not console input to the guest. This adds guest input as in

0d50a85f x86/pv-shim: shadow PV console's page for L2 DomU,

but with read_smb moved up in guest_tx.

Signed-off-by: Sarah Newman <srn@xxxxxxxxx>
---
 xen/arch/x86/guest/vixen.c        | 42 +++++++++++++++++++++++++++++++++++++++
 xen/drivers/char/console.c        |  6 +++++-
 xen/include/asm-x86/guest/vixen.h |  1 +
 3 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/guest/vixen.c b/xen/arch/x86/guest/vixen.c
index 08619d1..4491d82 100644
--- a/xen/arch/x86/guest/vixen.c
+++ b/xen/arch/x86/guest/vixen.c
@@ -245,6 +245,48 @@ static void vixen_interrupt(int irq, void *dev_id, struct 
cpu_user_regs *regs)
     vixen_upcall(smp_processor_id());
 }
 
+static void notify_guest(void)
+{
+    struct evtchn *chn;
+    chn = evtchn_from_port(hardware_domain, vixen_xencons_port);
+    evtchn_port_set_pending(hardware_domain, chn->notify_vcpu_id, chn);
+}
+
+size_t vixen_guest_tx(char c)
+{
+    size_t sent = 0;
+    volatile struct xencons_interface *r = vixen_xencons_iface;
+    XENCONS_RING_IDX cons, prod;
+
+    if (r == NULL)
+        return 0;
+
+    cons = ACCESS_ONCE(r->in_cons);
+    prod = r->in_prod;
+    /* Update pointers before accessing the ring */
+    smp_rmb();
+
+    ASSERT((prod - cons) <= sizeof(r->in));
+
+    /* Is the ring out of space? */
+    if ( sizeof(r->in) - (prod - cons) == 0 )
+        goto notify;
+
+
+    r->in[MASK_XENCONS_IDX(prod++, r->in)] = c;
+    sent++;
+
+    /* Write to the ring before updating the pointer */
+    smp_wmb();
+    ACCESS_ONCE(r->in_prod) = prod;
+
+ notify:
+    /* Always notify the guest: prevents receive path from getting stuck. */
+    notify_guest();
+
+    return sent;
+}
+
 bool vixen_ring_process(uint16_t port)
 {
     volatile struct xencons_interface *r = vixen_xencons_iface;
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index a83aeb2..be5875e 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -30,6 +30,7 @@
 #include <xen/hypercall.h> /* for do_console_io */
 #include <xen/early_printk.h>
 #include <xen/warning.h>
+#include <asm/guest/vixen.h>
 
 /* console: comma-separated list of console outputs. */
 static char __initdata opt_console[30] = OPT_CONSOLE_STR;
@@ -406,13 +407,16 @@ static void __serial_rx(char c, struct cpu_user_regs 
*regs)
         serial_rx_ring[SERIAL_RX_MASK(serial_rx_prod++)] = c;
     /* Always notify the guest: prevents receive path from getting stuck. */
     send_global_virq(VIRQ_CONSOLE);
+
+    if ( is_vixen())
+        vixen_guest_tx(c);
 }
 
 static void serial_rx(char c, struct cpu_user_regs *regs)
 {
     static int switch_code_count = 0;
 
-    if ( switch_code && (c == switch_code) )
+    if (!is_vixen() && switch_code && (c == switch_code) )
     {
         /* We eat CTRL-<switch_char> in groups of 3 to switch console input. */
         if ( ++switch_code_count == 3 )
diff --git a/xen/include/asm-x86/guest/vixen.h 
b/xen/include/asm-x86/guest/vixen.h
index eca263a..2e2666e 100644
--- a/xen/include/asm-x86/guest/vixen.h
+++ b/xen/include/asm-x86/guest/vixen.h
@@ -86,5 +86,6 @@ vixen_transform(struct domain *dom0,
                 xen_pfn_t *pconsole_mfn, uint32_t *pconsole_evtchn);
 
 bool vixen_ring_process(uint16_t port);
+size_t vixen_guest_tx(char c);
 
 #endif
-- 
1.9.1


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