From: Paul Durrant <pdurr...@amazon.com>
If the shared_info PFN cache has already been initialized then the content
of the shared_info page needs to be re-initialized whenever the guest
mode is (re)set.
Setting the guest mode is either done explicitly by the VMM via the
KVM_XEN_ATTR_TYPE_LONG_MODE attribute, or implicitly when the guest writes
the MSR to set up the hypercall page.
Signed-off-by: Paul Durrant <pdurr...@amazon.com>
Reviewed-by: David Woodhouse <d...@amazon.co.uk>
---
Cc: Sean Christopherson <sea...@google.com>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: David Woodhouse <dw...@infradead.org>
Cc: x...@kernel.org
v13:
- Patch title change.
v12:
- Fix missing update of return value if mode is not actually changed.
v11:
- Drop the hunk removing the call to kvm_xen_shared_info_init() when
KVM_XEN_ATTR_TYPE_SHARED_INFO is set; it was a mistake and causes self-
test failures.
v10:
- New in this version.
---
arch/x86/kvm/xen.c | 29 ++++++++++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 031e98d88ba2..52edf676c471 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -625,8 +625,16 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct
kvm_xen_hvm_attr *data)
} else {
mutex_lock(&kvm->arch.xen.xen_lock);
kvm->arch.xen.long_mode = !!data->u.long_mode;
+
+ /*
+ * Re-initialize shared_info to put the wallclock in the
+ * correct place. Whilst it's not necessary to do this
+ * unless the mode is actually changed, it does no harm
+ * to make the call anyway.
+ */
+ r = kvm->arch.xen.shinfo_cache.active ?
+ kvm_xen_shared_info_init(kvm) : 0;
mutex_unlock(&kvm->arch.xen.xen_lock);
- r = 0;
}
break;
@@ -1101,9 +1109,24 @@ int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu,
u64 data)
u32 page_num = data & ~PAGE_MASK;
u64 page_addr = data & PAGE_MASK;
bool lm = is_long_mode(vcpu);
+ int r = 0;
+
+ mutex_lock(&kvm->arch.xen.xen_lock);
+ if (kvm->arch.xen.long_mode != lm) {
+ kvm->arch.xen.long_mode = lm;
+
+ /*
+ * Re-initialize shared_info to put the wallclock in the
+ * correct place.
+ */
+ if (kvm->arch.xen.shinfo_cache.active &&
+ kvm_xen_shared_info_init(kvm))
+ r = 1;
+ }
+ mutex_unlock(&kvm->arch.xen.xen_lock);
- /* Latch long_mode for shared_info pages etc. */
- vcpu->kvm->arch.xen.long_mode = lm;
+ if (r)
+ return r;
/*
* If Xen hypercall intercept is enabled, fill the hypercall
--
2.39.2
