| Message ID | 20200218230310.29410-2-sean.j.christopherson@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: Minor emulator cleanup | expand |
On 2/19/2020 7:03 AM, Sean Christopherson wrote: > Add a new emulation type flag to explicitly mark emulation related to a > page fault. Move the propation of the GPA into the emulator from the > page fault handler into x86_emulate_instruction, using EMULTYPE_PF as an > indicator that cr2 is valid. Similarly, don't propagate cr2 into the > exception.address when it's *not* valid. > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > --- > arch/x86/include/asm/kvm_host.h | 12 +++++++++--- > arch/x86/kvm/mmu/mmu.c | 10 ++-------- > arch/x86/kvm/x86.c | 25 +++++++++++++++++++------ > 3 files changed, 30 insertions(+), 17 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 4dffbc10d3f8..10c1e8f472b6 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1370,8 +1370,9 @@ extern u64 kvm_mce_cap_supported; > * decode the instruction length. For use *only* by > * kvm_x86_ops->skip_emulated_instruction() implementations. > * > - * EMULTYPE_ALLOW_RETRY - Set when the emulator should resume the guest to > - * retry native execution under certain conditions. > + * EMULTYPE_ALLOW_RETRY_PF - Set when the emulator should resume the guest to > + * retry native execution under certain conditions, > + * Can only be set in conjunction with EMULTYPE_PF. > * > * EMULTYPE_TRAP_UD_FORCED - Set when emulating an intercepted #UD that was > * triggered by KVM's magic "force emulation" prefix, > @@ -1384,13 +1385,18 @@ extern u64 kvm_mce_cap_supported; > * backdoor emulation, which is opt in via module param. > * VMware backoor emulation handles select instructions > * and reinjects the #GP for all other cases. > + * > + * EMULTYPE_PF - Set when emulating MMIO by way of an intercepted #PF, in which > + * case the CR2/GPA value pass on the stack is valid. > */ > #define EMULTYPE_NO_DECODE (1 << 0) > #define EMULTYPE_TRAP_UD (1 << 1) > #define EMULTYPE_SKIP (1 << 2) > -#define EMULTYPE_ALLOW_RETRY (1 << 3) > +#define EMULTYPE_ALLOW_RETRY_PF (1 << 3) How about naming it as EMULTYPE_PF_ALLOW_RETRY and exchanging the bit position with EMULTYPE_PF ? > #define EMULTYPE_TRAP_UD_FORCED (1 << 4) > #define EMULTYPE_VMWARE_GP (1 << 5) > +#define EMULTYPE_PF (1 << 6) > + > int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type); > int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu, > void *insn, int insn_len); > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 7011a4e54866..258624d46588 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -5416,18 +5416,12 @@ EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt); > int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, > void *insn, int insn_len) > { > - int r, emulation_type = 0; > + int r, emulation_type = EMULTYPE_PF; > bool direct = vcpu->arch.mmu->direct_map; > > if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa))) > return RET_PF_RETRY; > > - /* With shadow page tables, fault_address contains a GVA or nGPA. */ > - if (vcpu->arch.mmu->direct_map) { > - vcpu->arch.gpa_available = true; > - vcpu->arch.gpa_val = cr2_or_gpa; > - } > - > r = RET_PF_INVALID; > if (unlikely(error_code & PFERR_RSVD_MASK)) { > r = handle_mmio_page_fault(vcpu, cr2_or_gpa, direct); > @@ -5472,7 +5466,7 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, > * for L1 isn't going to magically fix whatever issue cause L2 to fail. > */ > if (!mmio_info_in_cache(vcpu, cr2_or_gpa, direct) && !is_guest_mode(vcpu)) > - emulation_type = EMULTYPE_ALLOW_RETRY; > + emulation_type |= EMULTYPE_ALLOW_RETRY_PF; > emulate: > /* > * On AMD platforms, under certain conditions insn_len may be zero on #NPF. > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index fbabb2f06273..92af6c5a69e3 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -6483,10 +6483,11 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, > gpa_t gpa = cr2_or_gpa; > kvm_pfn_t pfn; > > - if (!(emulation_type & EMULTYPE_ALLOW_RETRY)) > + if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) > return false; > > - if (WARN_ON_ONCE(is_guest_mode(vcpu))) > + if (WARN_ON_ONCE(is_guest_mode(vcpu)) || > + WARN_ON_ONCE(!(emulation_type & EMULTYPE_PF))) > return false; > > if (!vcpu->arch.mmu->direct_map) { > @@ -6574,10 +6575,11 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, > */ > vcpu->arch.last_retry_eip = vcpu->arch.last_retry_addr = 0; > > - if (!(emulation_type & EMULTYPE_ALLOW_RETRY)) > + if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) > return false; > > - if (WARN_ON_ONCE(is_guest_mode(vcpu))) > + if (WARN_ON_ONCE(is_guest_mode(vcpu)) || > + WARN_ON_ONCE(!(emulation_type & EMULTYPE_PF))) > return false; > > if (x86_page_table_writing_insn(ctxt)) > @@ -6830,8 +6832,19 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, > } > > restart: > - /* Save the faulting GPA (cr2) in the address field */ > - ctxt->exception.address = cr2_or_gpa; > + if (emulation_type & EMULTYPE_PF) { > + /* Save the faulting GPA (cr2) in the address field */ > + ctxt->exception.address = cr2_or_gpa; > + > + /* With shadow page tables, cr2 contains a GVA or nGPA. */ > + if (vcpu->arch.mmu->direct_map) { > + vcpu->arch.gpa_available = true; > + vcpu->arch.gpa_val = cr2_or_gpa; > + } > + } else { > + /* Sanitize the address out of an abundance of paranoia. */ > + ctxt->exception.address = 0; > + } > > r = x86_emulate_insn(ctxt); > >
On Wed, Feb 19, 2020 at 05:01:41PM +0800, Xiaoyao Li wrote: > On 2/19/2020 7:03 AM, Sean Christopherson wrote: > >Add a new emulation type flag to explicitly mark emulation related to a > >page fault. Move the propation of the GPA into the emulator from the > >page fault handler into x86_emulate_instruction, using EMULTYPE_PF as an > >indicator that cr2 is valid. Similarly, don't propagate cr2 into the > >exception.address when it's *not* valid. > > > >Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > >--- > > arch/x86/include/asm/kvm_host.h | 12 +++++++++--- > > arch/x86/kvm/mmu/mmu.c | 10 ++-------- > > arch/x86/kvm/x86.c | 25 +++++++++++++++++++------ > > 3 files changed, 30 insertions(+), 17 deletions(-) > > > >diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > >index 4dffbc10d3f8..10c1e8f472b6 100644 > >--- a/arch/x86/include/asm/kvm_host.h > >+++ b/arch/x86/include/asm/kvm_host.h > >@@ -1370,8 +1370,9 @@ extern u64 kvm_mce_cap_supported; > > * decode the instruction length. For use *only* by > > * kvm_x86_ops->skip_emulated_instruction() implementations. > > * > >- * EMULTYPE_ALLOW_RETRY - Set when the emulator should resume the guest to > >- * retry native execution under certain conditions. > >+ * EMULTYPE_ALLOW_RETRY_PF - Set when the emulator should resume the guest to > >+ * retry native execution under certain conditions, > >+ * Can only be set in conjunction with EMULTYPE_PF. > > * > > * EMULTYPE_TRAP_UD_FORCED - Set when emulating an intercepted #UD that was > > * triggered by KVM's magic "force emulation" prefix, > >@@ -1384,13 +1385,18 @@ extern u64 kvm_mce_cap_supported; > > * backdoor emulation, which is opt in via module param. > > * VMware backoor emulation handles select instructions > > * and reinjects the #GP for all other cases. > >+ * > >+ * EMULTYPE_PF - Set when emulating MMIO by way of an intercepted #PF, in which > >+ * case the CR2/GPA value pass on the stack is valid. > > */ > > #define EMULTYPE_NO_DECODE (1 << 0) > > #define EMULTYPE_TRAP_UD (1 << 1) > > #define EMULTYPE_SKIP (1 << 2) > >-#define EMULTYPE_ALLOW_RETRY (1 << 3) > >+#define EMULTYPE_ALLOW_RETRY_PF (1 << 3) > > How about naming it as EMULTYPE_PF_ALLOW_RETRY and exchanging the bit > position with EMULTYPE_PF ? Hmm, EMULTYPE_PF_ALLOW_RETRY does sound better. I'm on the fence regarding shuffling the bits. If I were to shuffle the bits, I'd do a more thorough reorder so that the #UD and #PF types are consecutive, e.g. #define EMULTYPE_NO_DECODE (1 << 0) #define EMULTYPE_TRAP_UD (1 << 1) #define EMULTYPE_TRAP_UD_FORCED (1 << 2) #define EMULTYPE_SKIP (1 << 3) #define EMULTYPE_VMWARE_GP (1 << 4) #define EMULTYPE_PF (1 << 5) #define EMULTYPE_PF_ALLOW_RETRY (1 << 6) Part of me really wants to do that, the other part of me thinks it's unnecessary thrash. > > #define EMULTYPE_TRAP_UD_FORCED (1 << 4) > > #define EMULTYPE_VMWARE_GP (1 << 5) > >+#define EMULTYPE_PF (1 << 6) > >+ > > int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type); > > int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu, > > void *insn, int insn_len); > >diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > >index 7011a4e54866..258624d46588 100644 > >--- a/arch/x86/kvm/mmu/mmu.c > >+++ b/arch/x86/kvm/mmu/mmu.c > >@@ -5416,18 +5416,12 @@ EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt); > > int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, > > void *insn, int insn_len) > > { > >- int r, emulation_type = 0; > >+ int r, emulation_type = EMULTYPE_PF; > > bool direct = vcpu->arch.mmu->direct_map; > > if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa))) > > return RET_PF_RETRY; > >- /* With shadow page tables, fault_address contains a GVA or nGPA. */ > >- if (vcpu->arch.mmu->direct_map) { > >- vcpu->arch.gpa_available = true; > >- vcpu->arch.gpa_val = cr2_or_gpa; > >- } > >- > > r = RET_PF_INVALID; > > if (unlikely(error_code & PFERR_RSVD_MASK)) { > > r = handle_mmio_page_fault(vcpu, cr2_or_gpa, direct); > >@@ -5472,7 +5466,7 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, > > * for L1 isn't going to magically fix whatever issue cause L2 to fail. > > */ > > if (!mmio_info_in_cache(vcpu, cr2_or_gpa, direct) && !is_guest_mode(vcpu)) > >- emulation_type = EMULTYPE_ALLOW_RETRY; > >+ emulation_type |= EMULTYPE_ALLOW_RETRY_PF; > > emulate: > > /* > > * On AMD platforms, under certain conditions insn_len may be zero on #NPF. > >diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > >index fbabb2f06273..92af6c5a69e3 100644 > >--- a/arch/x86/kvm/x86.c > >+++ b/arch/x86/kvm/x86.c > >@@ -6483,10 +6483,11 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, > > gpa_t gpa = cr2_or_gpa; > > kvm_pfn_t pfn; > >- if (!(emulation_type & EMULTYPE_ALLOW_RETRY)) > >+ if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) > > return false; > >- if (WARN_ON_ONCE(is_guest_mode(vcpu))) > >+ if (WARN_ON_ONCE(is_guest_mode(vcpu)) || > >+ WARN_ON_ONCE(!(emulation_type & EMULTYPE_PF))) > > return false; > > if (!vcpu->arch.mmu->direct_map) { > >@@ -6574,10 +6575,11 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, > > */ > > vcpu->arch.last_retry_eip = vcpu->arch.last_retry_addr = 0; > >- if (!(emulation_type & EMULTYPE_ALLOW_RETRY)) > >+ if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) > > return false; > >- if (WARN_ON_ONCE(is_guest_mode(vcpu))) > >+ if (WARN_ON_ONCE(is_guest_mode(vcpu)) || > >+ WARN_ON_ONCE(!(emulation_type & EMULTYPE_PF))) > > return false; > > if (x86_page_table_writing_insn(ctxt)) > >@@ -6830,8 +6832,19 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, > > } > > restart: > >- /* Save the faulting GPA (cr2) in the address field */ > >- ctxt->exception.address = cr2_or_gpa; > >+ if (emulation_type & EMULTYPE_PF) { > >+ /* Save the faulting GPA (cr2) in the address field */ > >+ ctxt->exception.address = cr2_or_gpa; > >+ > >+ /* With shadow page tables, cr2 contains a GVA or nGPA. */ > >+ if (vcpu->arch.mmu->direct_map) { > >+ vcpu->arch.gpa_available = true; > >+ vcpu->arch.gpa_val = cr2_or_gpa; > >+ } > >+ } else { > >+ /* Sanitize the address out of an abundance of paranoia. */ > >+ ctxt->exception.address = 0; > >+ } > > r = x86_emulate_insn(ctxt); > > >
On 2/21/2020 4:11 AM, Sean Christopherson wrote: > On Wed, Feb 19, 2020 at 05:01:41PM +0800, Xiaoyao Li wrote: >> On 2/19/2020 7:03 AM, Sean Christopherson wrote: >>> Add a new emulation type flag to explicitly mark emulation related to a >>> page fault. Move the propation of the GPA into the emulator from the >>> page fault handler into x86_emulate_instruction, using EMULTYPE_PF as an >>> indicator that cr2 is valid. Similarly, don't propagate cr2 into the >>> exception.address when it's *not* valid. >>> >>> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> >>> --- >>> arch/x86/include/asm/kvm_host.h | 12 +++++++++--- >>> arch/x86/kvm/mmu/mmu.c | 10 ++-------- >>> arch/x86/kvm/x86.c | 25 +++++++++++++++++++------ >>> 3 files changed, 30 insertions(+), 17 deletions(-) >>> >>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >>> index 4dffbc10d3f8..10c1e8f472b6 100644 >>> --- a/arch/x86/include/asm/kvm_host.h >>> +++ b/arch/x86/include/asm/kvm_host.h >>> @@ -1370,8 +1370,9 @@ extern u64 kvm_mce_cap_supported; >>> * decode the instruction length. For use *only* by >>> * kvm_x86_ops->skip_emulated_instruction() implementations. >>> * >>> - * EMULTYPE_ALLOW_RETRY - Set when the emulator should resume the guest to >>> - * retry native execution under certain conditions. >>> + * EMULTYPE_ALLOW_RETRY_PF - Set when the emulator should resume the guest to >>> + * retry native execution under certain conditions, >>> + * Can only be set in conjunction with EMULTYPE_PF. >>> * >>> * EMULTYPE_TRAP_UD_FORCED - Set when emulating an intercepted #UD that was >>> * triggered by KVM's magic "force emulation" prefix, >>> @@ -1384,13 +1385,18 @@ extern u64 kvm_mce_cap_supported; >>> * backdoor emulation, which is opt in via module param. >>> * VMware backoor emulation handles select instructions >>> * and reinjects the #GP for all other cases. >>> + * >>> + * EMULTYPE_PF - Set when emulating MMIO by way of an intercepted #PF, in which >>> + * case the CR2/GPA value pass on the stack is valid. >>> */ >>> #define EMULTYPE_NO_DECODE (1 << 0) >>> #define EMULTYPE_TRAP_UD (1 << 1) >>> #define EMULTYPE_SKIP (1 << 2) >>> -#define EMULTYPE_ALLOW_RETRY (1 << 3) >>> +#define EMULTYPE_ALLOW_RETRY_PF (1 << 3) >> >> How about naming it as EMULTYPE_PF_ALLOW_RETRY and exchanging the bit >> position with EMULTYPE_PF ? > > Hmm, EMULTYPE_PF_ALLOW_RETRY does sound better. I'm on the fence regarding > shuffling the bits. If I were to shuffle the bits, I'd do a more thorough > reorder so that the #UD and #PF types are consecutive, e.g. > > #define EMULTYPE_NO_DECODE (1 << 0) > #define EMULTYPE_TRAP_UD (1 << 1) > #define EMULTYPE_TRAP_UD_FORCED (1 << 2) > #define EMULTYPE_SKIP (1 << 3) > #define EMULTYPE_VMWARE_GP (1 << 4) > #define EMULTYPE_PF (1 << 5) > #define EMULTYPE_PF_ALLOW_RETRY (1 << 6) > > Part of me really wants to do that, the other part of me thinks it's > unnecessary thrash. > I'm fine with thorough reorder, it helps read the codes. It's up to Paolo, anyway. >>> #define EMULTYPE_TRAP_UD_FORCED (1 << 4) >>> #define EMULTYPE_VMWARE_GP (1 << 5) >>> +#define EMULTYPE_PF (1 << 6) >>> + >>> int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type); >>> int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu, >>> void *insn, int insn_len); >>> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c >>> index 7011a4e54866..258624d46588 100644 >>> --- a/arch/x86/kvm/mmu/mmu.c >>> +++ b/arch/x86/kvm/mmu/mmu.c >>> @@ -5416,18 +5416,12 @@ EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt); >>> int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, >>> void *insn, int insn_len) >>> { >>> - int r, emulation_type = 0; >>> + int r, emulation_type = EMULTYPE_PF; >>> bool direct = vcpu->arch.mmu->direct_map; >>> if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa))) >>> return RET_PF_RETRY; >>> - /* With shadow page tables, fault_address contains a GVA or nGPA. */ >>> - if (vcpu->arch.mmu->direct_map) { >>> - vcpu->arch.gpa_available = true; >>> - vcpu->arch.gpa_val = cr2_or_gpa; >>> - } >>> - >>> r = RET_PF_INVALID; >>> if (unlikely(error_code & PFERR_RSVD_MASK)) { >>> r = handle_mmio_page_fault(vcpu, cr2_or_gpa, direct); >>> @@ -5472,7 +5466,7 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, >>> * for L1 isn't going to magically fix whatever issue cause L2 to fail. >>> */ >>> if (!mmio_info_in_cache(vcpu, cr2_or_gpa, direct) && !is_guest_mode(vcpu)) >>> - emulation_type = EMULTYPE_ALLOW_RETRY; >>> + emulation_type |= EMULTYPE_ALLOW_RETRY_PF; >>> emulate: >>> /* >>> * On AMD platforms, under certain conditions insn_len may be zero on #NPF. >>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>> index fbabb2f06273..92af6c5a69e3 100644 >>> --- a/arch/x86/kvm/x86.c >>> +++ b/arch/x86/kvm/x86.c >>> @@ -6483,10 +6483,11 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, >>> gpa_t gpa = cr2_or_gpa; >>> kvm_pfn_t pfn; >>> - if (!(emulation_type & EMULTYPE_ALLOW_RETRY)) >>> + if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) >>> return false; >>> - if (WARN_ON_ONCE(is_guest_mode(vcpu))) >>> + if (WARN_ON_ONCE(is_guest_mode(vcpu)) || >>> + WARN_ON_ONCE(!(emulation_type & EMULTYPE_PF))) >>> return false; >>> if (!vcpu->arch.mmu->direct_map) { >>> @@ -6574,10 +6575,11 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, >>> */ >>> vcpu->arch.last_retry_eip = vcpu->arch.last_retry_addr = 0; >>> - if (!(emulation_type & EMULTYPE_ALLOW_RETRY)) >>> + if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) >>> return false; >>> - if (WARN_ON_ONCE(is_guest_mode(vcpu))) >>> + if (WARN_ON_ONCE(is_guest_mode(vcpu)) || >>> + WARN_ON_ONCE(!(emulation_type & EMULTYPE_PF))) >>> return false; >>> if (x86_page_table_writing_insn(ctxt)) >>> @@ -6830,8 +6832,19 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, >>> } >>> restart: >>> - /* Save the faulting GPA (cr2) in the address field */ >>> - ctxt->exception.address = cr2_or_gpa; >>> + if (emulation_type & EMULTYPE_PF) { >>> + /* Save the faulting GPA (cr2) in the address field */ >>> + ctxt->exception.address = cr2_or_gpa; >>> + >>> + /* With shadow page tables, cr2 contains a GVA or nGPA. */ >>> + if (vcpu->arch.mmu->direct_map) { >>> + vcpu->arch.gpa_available = true; >>> + vcpu->arch.gpa_val = cr2_or_gpa; >>> + } >>> + } else { >>> + /* Sanitize the address out of an abundance of paranoia. */ >>> + ctxt->exception.address = 0; >>> + } >>> r = x86_emulate_insn(ctxt); >>> >>
On 20/02/20 21:11, Sean Christopherson wrote: >> How about naming it as EMULTYPE_PF_ALLOW_RETRY and exchanging the bit >> position with EMULTYPE_PF ? > Hmm, EMULTYPE_PF_ALLOW_RETRY does sound better. I'm on the fence regarding > shuffling the bits. If I were to shuffle the bits, I'd do a more thorough > reorder so that the #UD and #PF types are consecutive, e.g. Let's just change the name, I can do it. Paolo
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 4dffbc10d3f8..10c1e8f472b6 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1370,8 +1370,9 @@ extern u64 kvm_mce_cap_supported; * decode the instruction length. For use *only* by * kvm_x86_ops->skip_emulated_instruction() implementations. * - * EMULTYPE_ALLOW_RETRY - Set when the emulator should resume the guest to - * retry native execution under certain conditions. + * EMULTYPE_ALLOW_RETRY_PF - Set when the emulator should resume the guest to + * retry native execution under certain conditions, + * Can only be set in conjunction with EMULTYPE_PF. * * EMULTYPE_TRAP_UD_FORCED - Set when emulating an intercepted #UD that was * triggered by KVM's magic "force emulation" prefix, @@ -1384,13 +1385,18 @@ extern u64 kvm_mce_cap_supported; * backdoor emulation, which is opt in via module param. * VMware backoor emulation handles select instructions * and reinjects the #GP for all other cases. + * + * EMULTYPE_PF - Set when emulating MMIO by way of an intercepted #PF, in which + * case the CR2/GPA value pass on the stack is valid. */ #define EMULTYPE_NO_DECODE (1 << 0) #define EMULTYPE_TRAP_UD (1 << 1) #define EMULTYPE_SKIP (1 << 2) -#define EMULTYPE_ALLOW_RETRY (1 << 3) +#define EMULTYPE_ALLOW_RETRY_PF (1 << 3) #define EMULTYPE_TRAP_UD_FORCED (1 << 4) #define EMULTYPE_VMWARE_GP (1 << 5) +#define EMULTYPE_PF (1 << 6) + int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type); int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu, void *insn, int insn_len); diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 7011a4e54866..258624d46588 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5416,18 +5416,12 @@ EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt); int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, void *insn, int insn_len) { - int r, emulation_type = 0; + int r, emulation_type = EMULTYPE_PF; bool direct = vcpu->arch.mmu->direct_map; if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa))) return RET_PF_RETRY; - /* With shadow page tables, fault_address contains a GVA or nGPA. */ - if (vcpu->arch.mmu->direct_map) { - vcpu->arch.gpa_available = true; - vcpu->arch.gpa_val = cr2_or_gpa; - } - r = RET_PF_INVALID; if (unlikely(error_code & PFERR_RSVD_MASK)) { r = handle_mmio_page_fault(vcpu, cr2_or_gpa, direct); @@ -5472,7 +5466,7 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, * for L1 isn't going to magically fix whatever issue cause L2 to fail. */ if (!mmio_info_in_cache(vcpu, cr2_or_gpa, direct) && !is_guest_mode(vcpu)) - emulation_type = EMULTYPE_ALLOW_RETRY; + emulation_type |= EMULTYPE_ALLOW_RETRY_PF; emulate: /* * On AMD platforms, under certain conditions insn_len may be zero on #NPF. diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fbabb2f06273..92af6c5a69e3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6483,10 +6483,11 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, gpa_t gpa = cr2_or_gpa; kvm_pfn_t pfn; - if (!(emulation_type & EMULTYPE_ALLOW_RETRY)) + if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) return false; - if (WARN_ON_ONCE(is_guest_mode(vcpu))) + if (WARN_ON_ONCE(is_guest_mode(vcpu)) || + WARN_ON_ONCE(!(emulation_type & EMULTYPE_PF))) return false; if (!vcpu->arch.mmu->direct_map) { @@ -6574,10 +6575,11 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt, */ vcpu->arch.last_retry_eip = vcpu->arch.last_retry_addr = 0; - if (!(emulation_type & EMULTYPE_ALLOW_RETRY)) + if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) return false; - if (WARN_ON_ONCE(is_guest_mode(vcpu))) + if (WARN_ON_ONCE(is_guest_mode(vcpu)) || + WARN_ON_ONCE(!(emulation_type & EMULTYPE_PF))) return false; if (x86_page_table_writing_insn(ctxt)) @@ -6830,8 +6832,19 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, } restart: - /* Save the faulting GPA (cr2) in the address field */ - ctxt->exception.address = cr2_or_gpa; + if (emulation_type & EMULTYPE_PF) { + /* Save the faulting GPA (cr2) in the address field */ + ctxt->exception.address = cr2_or_gpa; + + /* With shadow page tables, cr2 contains a GVA or nGPA. */ + if (vcpu->arch.mmu->direct_map) { + vcpu->arch.gpa_available = true; + vcpu->arch.gpa_val = cr2_or_gpa; + } + } else { + /* Sanitize the address out of an abundance of paranoia. */ + ctxt->exception.address = 0; + } r = x86_emulate_insn(ctxt);
Add a new emulation type flag to explicitly mark emulation related to a page fault. Move the propation of the GPA into the emulator from the page fault handler into x86_emulate_instruction, using EMULTYPE_PF as an indicator that cr2 is valid. Similarly, don't propagate cr2 into the exception.address when it's *not* valid. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> --- arch/x86/include/asm/kvm_host.h | 12 +++++++++--- arch/x86/kvm/mmu/mmu.c | 10 ++-------- arch/x86/kvm/x86.c | 25 +++++++++++++++++++------ 3 files changed, 30 insertions(+), 17 deletions(-)