[PATCH v8 15/16] xen/vmtrace: support for VM forks

From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xenproject.org>
Cc: "Tamas K Lengyel" <tamas.lengyel@intel.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Jan Beulich" <JBeulich@suse.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
	"Jun Nakajima" <jun.nakajima@intel.com>,
	"Kevin Tian" <kevin.tian@intel.com>,
	"Michał Leszczyński" <michal.leszczynski@cert.pl>,
	"Tamas K Lengyel" <tamas@tklengyel.com>
Subject: [PATCH v8 15/16] xen/vmtrace: support for VM forks
Date: Sat, 30 Jan 2021 02:58:51 +0000	[thread overview]
Message-ID: <20210130025852.12430-16-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <20210130025852.12430-1-andrew.cooper3@citrix.com>

From: Tamas K Lengyel <tamas.lengyel@intel.com>

Implement vmtrace_reset_pt function. Properly set IPT
state for VM forks.

Signed-off-by: Tamas K Lengyel <tamas.lengyel@intel.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Wei Liu <wl@xen.org>
CC: Jun Nakajima <jun.nakajima@intel.com>
CC: Kevin Tian <kevin.tian@intel.com>
CC: Michał Leszczyński <michal.leszczynski@cert.pl>
CC: Tamas K Lengyel <tamas@tklengyel.com>

v7:
 * New
---
 xen/arch/x86/hvm/vmx/vmx.c    | 11 +++++++++++
 xen/arch/x86/mm/mem_sharing.c |  3 +++
 xen/include/asm-x86/hvm/hvm.h |  9 +++++++++
 3 files changed, 23 insertions(+)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index a64c4e4177..5a33d8024e 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2412,6 +2412,16 @@ static int vmtrace_output_position(struct vcpu *v, uint64_t *pos)
     return v->arch.hvm.vmx.ipt_active;
 }
 
+static int vmtrace_reset(struct vcpu *v)
+{
+    if ( !v->arch.hvm.vmx.ipt_active )
+        return -EINVAL;
+
+    v->arch.msrs->rtit.output_offset = 0;
+    v->arch.msrs->rtit.status = 0;
+    return 0;
+}
+
 static struct hvm_function_table __initdata vmx_function_table = {
     .name                 = "VMX",
     .cpu_up_prepare       = vmx_cpu_up_prepare,
@@ -2471,6 +2481,7 @@ static struct hvm_function_table __initdata vmx_function_table = {
     .vmtrace_output_position = vmtrace_output_position,
     .vmtrace_set_option = vmtrace_set_option,
     .vmtrace_get_option = vmtrace_get_option,
+    .vmtrace_reset = vmtrace_reset,
     .tsc_scaling = {
         .max_ratio = VMX_TSC_MULTIPLIER_MAX,
     },
diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index adaeab4612..00ada05c10 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -1632,6 +1632,8 @@ static int copy_vcpu_settings(struct domain *cd, const struct domain *d)
             copy_domain_page(new_vcpu_info_mfn, vcpu_info_mfn);
         }
 
+        hvm_vmtrace_reset(cd_vcpu);
+
         /*
          * TODO: to support VMs with PV interfaces copy additional
          * settings here, such as PV timers.
@@ -1782,6 +1784,7 @@ static int fork(struct domain *cd, struct domain *d)
         cd->max_pages = d->max_pages;
         *cd->arch.cpuid = *d->arch.cpuid;
         *cd->arch.msr = *d->arch.msr;
+        cd->vmtrace_size = d->vmtrace_size;
         cd->parent = d;
     }
 
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 960ec03917..150746de66 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -219,6 +219,7 @@ struct hvm_function_table {
     int (*vmtrace_output_position)(struct vcpu *v, uint64_t *pos);
     int (*vmtrace_set_option)(struct vcpu *v, uint64_t key, uint64_t value);
     int (*vmtrace_get_option)(struct vcpu *v, uint64_t key, uint64_t *value);
+    int (*vmtrace_reset)(struct vcpu *v);
 
     /*
      * Parameters and callbacks for hardware-assisted TSC scaling,
@@ -696,6 +697,14 @@ static inline int hvm_vmtrace_get_option(
     return -EOPNOTSUPP;
 }
 
+static inline int hvm_vmtrace_reset(struct vcpu *v)
+{
+    if ( hvm_funcs.vmtrace_reset )
+        return hvm_funcs.vmtrace_reset(v);
+
+    return -EOPNOTSUPP;
+}
+
 /*
  * This must be defined as a macro instead of an inline function,
  * because it uses 'struct vcpu' and 'struct domain' which have
-- 
2.11.0


