| Message ID | 20220718074756.53788-1-yu.c.zhang@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] KVM: X86: Explicitly set the 'fault.async_page_fault' value in kvm_fixup_and_inject_pf_error(). | expand |
On Mon, Jul 18, 2022, Yu Zhang wrote: > kvm_fixup_and_inject_pf_error() was introduced to fixup the error code( > e.g., to add RSVD flag) and inject the #PF to the guest, when guest > MAXPHYADDR is smaller than the host one. > > When it comes to nested, L0 is expected to intercept and fix up the #PF > and then inject to L2 directly if > - L2.MAXPHYADDR < L0.MAXPHYADDR and > - L1 has no intention to intercept L2's #PF (e.g., L2 and L1 have the > same MAXPHYADDR value && L1 is using EPT for L2), > instead of constructing a #PF VM Exit to L1. Currently, with PFEC_MASK > and PFEC_MATCH both set to 0 in vmcs02, the interception and injection > may happen on all L2 #PFs. > > However, failing to initialize 'fault' in kvm_fixup_and_inject_pf_error() > may cause the fault.async_page_fault being NOT zeroed, and later the #PF > being treated as a nested async page fault, and then being injected to L1. > Instead of zeroing 'fault' at the beginning of this function, we mannually > set the value of 'fault.async_page_fault', because false is the value we > really expect. > > Fixes: 897861479c064 ("KVM: x86: Add helper functions for illegal GPA checking and page fault injection") > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216178 > Reported-by: Yang Lixiao <lixiao.yang@intel.com> > Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> > Signed-off-by: Sean Christopherson <seanjc@google.com> No need for my SoB, I was just providing feedback. Other than that, Reviewed-by: Sean Christopherson <seanjc@google.com>
On Tue, Jul 19, 2022 at 07:01:41PM +0000, Sean Christopherson wrote: > On Mon, Jul 18, 2022, Yu Zhang wrote: > > kvm_fixup_and_inject_pf_error() was introduced to fixup the error code( > > e.g., to add RSVD flag) and inject the #PF to the guest, when guest > > MAXPHYADDR is smaller than the host one. > > > > When it comes to nested, L0 is expected to intercept and fix up the #PF > > and then inject to L2 directly if > > - L2.MAXPHYADDR < L0.MAXPHYADDR and > > - L1 has no intention to intercept L2's #PF (e.g., L2 and L1 have the > > same MAXPHYADDR value && L1 is using EPT for L2), > > instead of constructing a #PF VM Exit to L1. Currently, with PFEC_MASK > > and PFEC_MATCH both set to 0 in vmcs02, the interception and injection > > may happen on all L2 #PFs. > > > > However, failing to initialize 'fault' in kvm_fixup_and_inject_pf_error() > > may cause the fault.async_page_fault being NOT zeroed, and later the #PF > > being treated as a nested async page fault, and then being injected to L1. > > Instead of zeroing 'fault' at the beginning of this function, we mannually > > set the value of 'fault.async_page_fault', because false is the value we > > really expect. > > > > Fixes: 897861479c064 ("KVM: x86: Add helper functions for illegal GPA checking and page fault injection") > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216178 > > Reported-by: Yang Lixiao <lixiao.yang@intel.com> > > Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> > > Signed-off-by: Sean Christopherson <seanjc@google.com> > > No need for my SoB, I was just providing feedback. Other than that, > Thanks! It's a very detailed suggestion. :) > Reviewed-by: Sean Christopherson <seanjc@google.com> > @Paolo Any comment on this fix, and on the test case change(https://www.spinics.net/lists/kvm/msg283600.html)? Thanks! B.R. Yu
On Thu, Jul 21, 2022 at 05:22:14PM +0800, Yu Zhang wrote: > On Tue, Jul 19, 2022 at 07:01:41PM +0000, Sean Christopherson wrote: > > On Mon, Jul 18, 2022, Yu Zhang wrote: > > > kvm_fixup_and_inject_pf_error() was introduced to fixup the error code( > > > e.g., to add RSVD flag) and inject the #PF to the guest, when guest > > > MAXPHYADDR is smaller than the host one. > > > > > > When it comes to nested, L0 is expected to intercept and fix up the #PF > > > and then inject to L2 directly if > > > - L2.MAXPHYADDR < L0.MAXPHYADDR and > > > - L1 has no intention to intercept L2's #PF (e.g., L2 and L1 have the > > > same MAXPHYADDR value && L1 is using EPT for L2), > > > instead of constructing a #PF VM Exit to L1. Currently, with PFEC_MASK > > > and PFEC_MATCH both set to 0 in vmcs02, the interception and injection > > > may happen on all L2 #PFs. > > > > > > However, failing to initialize 'fault' in kvm_fixup_and_inject_pf_error() > > > may cause the fault.async_page_fault being NOT zeroed, and later the #PF > > > being treated as a nested async page fault, and then being injected to L1. > > > Instead of zeroing 'fault' at the beginning of this function, we mannually > > > set the value of 'fault.async_page_fault', because false is the value we > > > really expect. > > > > > > Fixes: 897861479c064 ("KVM: x86: Add helper functions for illegal GPA checking and page fault injection") > > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216178 > > > Reported-by: Yang Lixiao <lixiao.yang@intel.com> > > > Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> > > > Signed-off-by: Sean Christopherson <seanjc@google.com> > > > > No need for my SoB, I was just providing feedback. Other than that, > > > Thanks! It's a very detailed suggestion. :) > > > Reviewed-by: Sean Christopherson <seanjc@google.com> > > > > @Paolo Any comment on this fix, and on the test case change(https://www.spinics.net/lists/kvm/msg283600.html)? Thanks! > > B.R. > Yu Ping... Or should I send another version? Thanks! B.R. Yu
On Thu, Aug 04, 2022, Yu Zhang wrote: > On Thu, Jul 21, 2022 at 05:22:14PM +0800, Yu Zhang wrote: > > On Tue, Jul 19, 2022 at 07:01:41PM +0000, Sean Christopherson wrote: > > > On Mon, Jul 18, 2022, Yu Zhang wrote: > > > > kvm_fixup_and_inject_pf_error() was introduced to fixup the error code( > > > > e.g., to add RSVD flag) and inject the #PF to the guest, when guest > > > > MAXPHYADDR is smaller than the host one. > > > > > > > > When it comes to nested, L0 is expected to intercept and fix up the #PF > > > > and then inject to L2 directly if > > > > - L2.MAXPHYADDR < L0.MAXPHYADDR and > > > > - L1 has no intention to intercept L2's #PF (e.g., L2 and L1 have the > > > > same MAXPHYADDR value && L1 is using EPT for L2), > > > > instead of constructing a #PF VM Exit to L1. Currently, with PFEC_MASK > > > > and PFEC_MATCH both set to 0 in vmcs02, the interception and injection > > > > may happen on all L2 #PFs. > > > > > > > > However, failing to initialize 'fault' in kvm_fixup_and_inject_pf_error() > > > > may cause the fault.async_page_fault being NOT zeroed, and later the #PF > > > > being treated as a nested async page fault, and then being injected to L1. > > > > Instead of zeroing 'fault' at the beginning of this function, we mannually > > > > set the value of 'fault.async_page_fault', because false is the value we > > > > really expect. > > > > > > > > Fixes: 897861479c064 ("KVM: x86: Add helper functions for illegal GPA checking and page fault injection") > > > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216178 > > > > Reported-by: Yang Lixiao <lixiao.yang@intel.com> > > > > Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> > > > > Signed-off-by: Sean Christopherson <seanjc@google.com> > > > > > > No need for my SoB, I was just providing feedback. Other than that, > > > > > Thanks! It's a very detailed suggestion. :) > > > > > Reviewed-by: Sean Christopherson <seanjc@google.com> > > > > > > > @Paolo Any comment on this fix, and on the test case change(https://www.spinics.net/lists/kvm/msg283600.html)? Thanks! > > > > B.R. > > Yu > > Ping... Or should I send another version? Thanks! Shouldn't need to send a new version. Paolo, can you grab this for 6.0-rc1?
Queued, thanks. Paolo
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 031678eff28e..ffd8c96cfaa5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12999,6 +12999,7 @@ void kvm_fixup_and_inject_pf_error(struct kvm_vcpu *vcpu, gva_t gva, u16 error_c fault.error_code = error_code; fault.nested_page_fault = false; fault.address = gva; + fault.async_page_fault = false; } vcpu->arch.walk_mmu->inject_page_fault(vcpu, &fault); }
kvm_fixup_and_inject_pf_error() was introduced to fixup the error code( e.g., to add RSVD flag) and inject the #PF to the guest, when guest MAXPHYADDR is smaller than the host one. When it comes to nested, L0 is expected to intercept and fix up the #PF and then inject to L2 directly if - L2.MAXPHYADDR < L0.MAXPHYADDR and - L1 has no intention to intercept L2's #PF (e.g., L2 and L1 have the same MAXPHYADDR value && L1 is using EPT for L2), instead of constructing a #PF VM Exit to L1. Currently, with PFEC_MASK and PFEC_MATCH both set to 0 in vmcs02, the interception and injection may happen on all L2 #PFs. However, failing to initialize 'fault' in kvm_fixup_and_inject_pf_error() may cause the fault.async_page_fault being NOT zeroed, and later the #PF being treated as a nested async page fault, and then being injected to L1. Instead of zeroing 'fault' at the beginning of this function, we mannually set the value of 'fault.async_page_fault', because false is the value we really expect. Fixes: 897861479c064 ("KVM: x86: Add helper functions for illegal GPA checking and page fault injection") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216178 Reported-by: Yang Lixiao <lixiao.yang@intel.com> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> --- v2: - Set 'fault.async_page_fault' mannually to false, instead of initializing the whole structure based on Sean's suggestion. - Commit message changes based on the code change. --- arch/x86/kvm/x86.c | 1 + 1 file changed, 1 insertion(+)