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| author | Paul Durrant <pdurrant@amazon.com> | 2024-02-15 15:29:06 +0000 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-02-20 07:37:48 -0800 |
| commit | 18b99e4d6db65fface45f1e9bcd1041d93c1ac66 (patch) | |
| tree | 818e13df45bf93848a69386625ba03b07aebbd5a /arch | |
| parent | c01c55a34f284d27719638c4398282442c13ca34 (diff) | |
| download | linux-stable-18b99e4d6db65fface45f1e9bcd1041d93c1ac66.tar.gz linux-stable-18b99e4d6db65fface45f1e9bcd1041d93c1ac66.tar.bz2 linux-stable-18b99e4d6db65fface45f1e9bcd1041d93c1ac66.zip | |
KVM: x86/xen: re-initialize shared_info if guest (32/64-bit) mode is set
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 <pdurrant@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20240215152916.1158-12-paul@xen.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/xen.c | 29 |
1 files 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 |