[XEN PATCH v12 4/7] x86/domctl: Add hypercall to set the access of x86 gsi

[Jiqian Chen <Jiqian.Chen@xxxxxxx>]

Some type of domains don't have PIRQs, like PVH, it doesn't do
PHYSDEVOP_map_pirq for each gsi. When passthrough a device
to guest base on PVH dom0, callstack
pci_add_dm_done->XEN_DOMCTL_irq_permission will fail at function
domain_pirq_to_irq, because PVH has no mapping of gsi, pirq and
irq on Xen side.
What's more, current hypercall XEN_DOMCTL_irq_permission requires
passing in pirq to set the access of irq, it is not suitable for
dom0 that doesn't have PIRQs.

So, add a new hypercall XEN_DOMCTL_gsi_permission to grant/deny
the permission of irq(translate from x86 gsi) to dumU when dom0
has no PIRQs.

Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
---
CC: Daniel P . Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
Remaining comment @Daniel P . Smith:
+        ret = -EPERM;
+        if ( !irq_access_permitted(currd, irq) ||
+             xsm_irq_permission(XSM_HOOK, d, irq, access_flag) )
+            goto gsi_permission_out;
Is it okay to issue the XSM check using the translated value, 
not the one that was originally passed into the hypercall?
---
 xen/arch/x86/domctl.c              | 32 ++++++++++++++++++++++++++++++
 xen/arch/x86/include/asm/io_apic.h |  2 ++
 xen/arch/x86/io_apic.c             | 17 ++++++++++++++++
 xen/arch/x86/mpparse.c             |  5 ++---
 xen/include/public/domctl.h        |  9 +++++++++
 xen/xsm/flask/hooks.c              |  1 +
 6 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 9190e11faaa3..4e9e4c4cfed3 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -36,6 +36,7 @@
 #include <asm/xstate.h>
 #include <asm/psr.h>
 #include <asm/cpu-policy.h>
+#include <asm/io_apic.h>
 
 static int update_domain_cpu_policy(struct domain *d,
                                     xen_domctl_cpu_policy_t *xdpc)
@@ -237,6 +238,37 @@ long arch_do_domctl(
         break;
     }
 
+    case XEN_DOMCTL_gsi_permission:
+    {
+        int irq;
+        unsigned int gsi = domctl->u.gsi_permission.gsi;
+        uint8_t access_flag = domctl->u.gsi_permission.access_flag;
+
+        /* Check all bits and pads are zero except lowest bit */
+        ret = -EINVAL;
+        if ( access_flag & ( ~XEN_DOMCTL_GSI_PERMISSION_MASK ) )
+            goto gsi_permission_out;
+        for ( i = 0; i < ARRAY_SIZE(domctl->u.gsi_permission.pad); ++i )
+            if ( domctl->u.gsi_permission.pad[i] )
+                goto gsi_permission_out;
+
+        if ( gsi > highest_gsi() || (irq = gsi_2_irq(gsi)) <= 0 )
+            goto gsi_permission_out;
+
+        ret = -EPERM;
+        if ( !irq_access_permitted(currd, irq) ||
+             xsm_irq_permission(XSM_HOOK, d, irq, access_flag) )
+            goto gsi_permission_out;
+
+        if ( access_flag )
+            ret = irq_permit_access(d, irq);
+        else
+            ret = irq_deny_access(d, irq);
+
+    gsi_permission_out:
+        break;
+    }
+
     case XEN_DOMCTL_getpageframeinfo3:
     {
         unsigned int num = domctl->u.getpageframeinfo3.num;
diff --git a/xen/arch/x86/include/asm/io_apic.h 
b/xen/arch/x86/include/asm/io_apic.h
index 78268ea8f666..7e86d8337758 100644
--- a/xen/arch/x86/include/asm/io_apic.h
+++ b/xen/arch/x86/include/asm/io_apic.h
@@ -213,5 +213,7 @@ unsigned highest_gsi(void);
 
 int ioapic_guest_read( unsigned long physbase, unsigned int reg, u32 *pval);
 int ioapic_guest_write(unsigned long physbase, unsigned int reg, u32 val);
+int mp_find_ioapic(int gsi);
+int gsi_2_irq(int gsi);
 
 #endif
diff --git a/xen/arch/x86/io_apic.c b/xen/arch/x86/io_apic.c
index d2a313c4ac72..5968c8055671 100644
--- a/xen/arch/x86/io_apic.c
+++ b/xen/arch/x86/io_apic.c
@@ -955,6 +955,23 @@ static int pin_2_irq(int idx, int apic, int pin)
     return irq;
 }
 
+int gsi_2_irq(int gsi)
+{
+    int ioapic, pin, irq;
+
+    ioapic = mp_find_ioapic(gsi);
+    if ( ioapic < 0 )
+        return -EINVAL;
+
+    pin = gsi - io_apic_gsi_base(ioapic);
+
+    irq = apic_pin_2_gsi_irq(ioapic, pin);
+    if ( irq <= 0 )
+        return -EINVAL;
+
+    return irq;
+}
+
 static inline int IO_APIC_irq_trigger(int irq)
 {
     int apic, idx, pin;
diff --git a/xen/arch/x86/mpparse.c b/xen/arch/x86/mpparse.c
index d8ccab2449c6..7786a3337760 100644
--- a/xen/arch/x86/mpparse.c
+++ b/xen/arch/x86/mpparse.c
@@ -841,8 +841,7 @@ static struct mp_ioapic_routing {
 } mp_ioapic_routing[MAX_IO_APICS];
 
 
-static int mp_find_ioapic (
-       int                     gsi)
+int mp_find_ioapic(int gsi)
 {
        unsigned int            i;
 
@@ -914,7 +913,7 @@ void __init mp_register_ioapic (
        return;
 }
 
-unsigned __init highest_gsi(void)
+unsigned highest_gsi(void)
 {
        unsigned x, res = 0;
        for (x = 0; x < nr_ioapics; x++)
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 2a49fe46ce25..877e35ab1376 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -464,6 +464,13 @@ struct xen_domctl_irq_permission {
     uint8_t pad[3];
 };
 
+/* XEN_DOMCTL_gsi_permission */
+struct xen_domctl_gsi_permission {
+    uint32_t gsi;
+#define XEN_DOMCTL_GSI_PERMISSION_MASK 1
+    uint8_t access_flag;    /* flag to specify enable/disable of x86 gsi 
access */
+    uint8_t pad[3];
+};
 
 /* XEN_DOMCTL_iomem_permission */
 struct xen_domctl_iomem_permission {
@@ -1306,6 +1313,7 @@ struct xen_domctl {
 #define XEN_DOMCTL_get_paging_mempool_size       85
 #define XEN_DOMCTL_set_paging_mempool_size       86
 #define XEN_DOMCTL_dt_overlay                    87
+#define XEN_DOMCTL_gsi_permission                88
 #define XEN_DOMCTL_gdbsx_guestmemio            1000
 #define XEN_DOMCTL_gdbsx_pausevcpu             1001
 #define XEN_DOMCTL_gdbsx_unpausevcpu           1002
@@ -1328,6 +1336,7 @@ struct xen_domctl {
         struct xen_domctl_setdomainhandle   setdomainhandle;
         struct xen_domctl_setdebugging      setdebugging;
         struct xen_domctl_irq_permission    irq_permission;
+        struct xen_domctl_gsi_permission    gsi_permission;
         struct xen_domctl_iomem_permission  iomem_permission;
         struct xen_domctl_ioport_permission ioport_permission;
         struct xen_domctl_hypercall_init    hypercall_init;
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 5e88c71b8e22..a5b134c91101 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -685,6 +685,7 @@ static int cf_check flask_domctl(struct domain *d, int cmd)
     case XEN_DOMCTL_shadow_op:
     case XEN_DOMCTL_ioport_permission:
     case XEN_DOMCTL_ioport_mapping:
+    case XEN_DOMCTL_gsi_permission:
 #endif
 #ifdef CONFIG_HAS_PASSTHROUGH
     /*
-- 
2.34.1