[Xen-devel] [PATCH] Fix save/restore for HVM domains with viridian=1

[Paul Durrant <paul.durrant@xxxxxxxxxx>]

# HG changeset patch
# User Paul Durrant <paul.durrant@xxxxxxxxxx>
# Date 1322232651 0
# Node ID a3c5e87c73a991861fcdd9a5a1eb8ebc635a2d09
# Parent  0a0c02a616768bfab16c072788cb76be1893c37f
Fix save/restore for HVM domains with viridian=1

xc_domain_save/restore currently pay no attention to HVM_PARAM_VIRIDIAN which
results in an HVM domain running a recent version on Windows (post-Vista)
locking up on a domain restore due to EOIs (done via a viridian MSR write)
being silently dropped.
This patch adds an extra save entry for the viridian parameter and also
adds code in the viridian kernel module to catch attempted use of viridian
functionality when the HVM parameter has not been set.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

diff -r 0a0c02a61676 -r a3c5e87c73a9 tools/libxc/xc_domain_restore.c
--- a/tools/libxc/xc_domain_restore.c   Mon Nov 21 21:28:34 2011 +0000
+++ b/tools/libxc/xc_domain_restore.c   Fri Nov 25 14:50:51 2011 +0000
@@ -675,6 +675,7 @@ typedef struct {
     uint64_t vm86_tss;
     uint64_t console_pfn;
     uint64_t acpi_ioport_location;
+    uint64_t viridian;
 } pagebuf_t;
 
 static int pagebuf_init(pagebuf_t* buf)
@@ -809,6 +810,16 @@ static int pagebuf_get_one(xc_interface 
         }
         return pagebuf_get_one(xch, ctx, buf, fd, dom);
 
+    case XC_SAVE_ID_HVM_VIRIDIAN:
+        /* Skip padding 4 bytes then read the acpi ioport location. */
+        if ( RDEXACT(fd, &buf->viridian, sizeof(uint32_t)) ||
+             RDEXACT(fd, &buf->viridian, sizeof(uint64_t)) )
+        {
+            PERROR("error read the viridian flag");
+            return -1;
+        }
+        return pagebuf_get_one(xch, ctx, buf, fd, dom);
+
     default:
         if ( (count > MAX_BATCH_SIZE) || (count < 0) ) {
             ERROR("Max batch size exceeded (%d). Giving up.", count);
@@ -1440,6 +1451,9 @@ int xc_domain_restore(xc_interface *xch,
             fcntl(io_fd, F_SETFL, orig_io_fd_flags | O_NONBLOCK);
     }
 
+    if (pagebuf.viridian != 0)
+        xc_set_hvm_param(xch, dom, HVM_PARAM_VIRIDIAN, 1);
+
     if (pagebuf.acpi_ioport_location == 1) {
         DBGPRINTF("Use new firmware ioport from the checkpoint\n");
         xc_set_hvm_param(xch, dom, HVM_PARAM_ACPI_IOPORTS_LOCATION, 1);
diff -r 0a0c02a61676 -r a3c5e87c73a9 tools/libxc/xc_domain_save.c
--- a/tools/libxc/xc_domain_save.c      Mon Nov 21 21:28:34 2011 +0000
+++ b/tools/libxc/xc_domain_save.c      Fri Nov 25 14:50:51 2011 +0000
@@ -1506,6 +1506,18 @@ int xc_domain_save(xc_interface *xch, in
             PERROR("Error when writing the firmware ioport version");
             goto out;
         }
+
+        chunk.id = XC_SAVE_ID_HVM_VIRIDIAN;
+        chunk.data = 0;
+        xc_get_hvm_param(xch, dom, HVM_PARAM_VIRIDIAN,
+                         (unsigned long *)&chunk.data);
+
+        if ( (chunk.data != 0) &&
+             wrexact(io_fd, &chunk, sizeof(chunk)) )
+        {
+            PERROR("Error when writing the viridian flag");
+            goto out;
+        }
     }
 
     if ( !callbacks->checkpoint )
diff -r 0a0c02a61676 -r a3c5e87c73a9 tools/libxc/xg_save_restore.h
--- a/tools/libxc/xg_save_restore.h     Mon Nov 21 21:28:34 2011 +0000
+++ b/tools/libxc/xg_save_restore.h     Fri Nov 25 14:50:51 2011 +0000
@@ -134,6 +134,7 @@
 #define XC_SAVE_ID_HVM_CONSOLE_PFN    -8 /* (HVM-only) */
 #define XC_SAVE_ID_LAST_CHECKPOINT    -9 /* Commit to restoring after 
completion of current iteration. */
 #define XC_SAVE_ID_HVM_ACPI_IOPORTS_LOCATION -10
+#define XC_SAVE_ID_HVM_VIRIDIAN       -11
 
 /*
 ** We process save/restore/migrate in batches of pages; the below
diff -r 0a0c02a61676 -r a3c5e87c73a9 xen/arch/x86/hvm/viridian.c
--- a/xen/arch/x86/hvm/viridian.c       Mon Nov 21 21:28:34 2011 +0000
+++ b/xen/arch/x86/hvm/viridian.c       Fri Nov 25 14:50:51 2011 +0000
@@ -206,8 +206,11 @@ int wrmsr_viridian_regs(uint32_t idx, ui
     struct vcpu *v = current;
     struct domain *d = v->domain;
 
-    if ( !is_viridian_domain(d) )
+    if ( !is_viridian_domain(d) ) {
+        gdprintk(XENLOG_WARNING, "%s: %d not a viridian domain\n", __func__,
+                 d->domain_id);
         return 0;
+    }
 
     switch ( idx )
     {
@@ -271,8 +274,11 @@ int rdmsr_viridian_regs(uint32_t idx, ui
     struct vcpu *v = current;
     struct domain *d = v->domain;
     
-    if ( !is_viridian_domain(d) )
+    if ( !is_viridian_domain(d) ) {
+        gdprintk(XENLOG_WARNING, "%s: %d not a viridian domain\n", __func__,
+                 d->domain_id);
         return 0;
+    }
 
     switch ( idx )
     {
@@ -411,6 +417,8 @@ static int viridian_load_domain_ctxt(str
     if ( hvm_load_entry(VIRIDIAN_DOMAIN, h, &ctxt) != 0 )
         return -EINVAL;
 
+    ASSERT(is_viridian_domain(d));
+
     d->arch.hvm_domain.viridian.hypercall_gpa.raw = ctxt.hypercall_gpa;
     d->arch.hvm_domain.viridian.guest_os_id.raw   = ctxt.guest_os_id;
 
@@ -455,6 +463,8 @@ static int viridian_load_vcpu_ctxt(struc
     if ( hvm_load_entry(VIRIDIAN_VCPU, h, &ctxt) != 0 )
         return -EINVAL;
 
+    ASSERT(is_viridian_domain(d));
+
     v->arch.hvm_vcpu.viridian.apic_assist.raw = ctxt.apic_assist;
 
     return 0;

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