| Message ID | 1537970184-44348-7-git-send-email-julien.thierry@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Ensure stack is aligned for kernel entries | expand |
On Wed, Sep 26, 2018 at 02:56:23PM +0100, Julien Thierry wrote: > When an EL2 entry of __kvm_hyp_vector is taken, it means an entry from a > lower EL was previously taken to exit the guest. Taking that lower EL entry > already applied vector hardening if needed, so there is no need to do it > again. > > Only apply vector hardening for exception coming from lower EL. > > Signed-off-by: Julien Thierry <julien.thierry@arm.com> > Cc: kvmarm@lists.cs.columbia.edu > --- > arch/arm64/kvm/hyp/hyp-entry.S | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S > index 24b4fba..da31386 100644 > --- a/arch/arm64/kvm/hyp/hyp-entry.S > +++ b/arch/arm64/kvm/hyp/hyp-entry.S > @@ -257,7 +257,15 @@ ENTRY(__kvm_hyp_vector) > ENDPROC(__kvm_hyp_vector) > > #ifdef CONFIG_KVM_INDIRECT_VECTORS > -.macro hyp_ventry > +.macro hyp_el2_ventry > + .align 7 > +1: b __kvm_hyp_vector + (1b - 0b) > + .rept 31 > + nop > + .endr > +.endm > + > +.macro hyp_el1_ventry > .align 7 > 1: .rept 27 > nop > @@ -290,8 +298,11 @@ alternative_cb_end I think it would be cleaner to take the EL as a macro parameter, but again, I defer to Marc and Christoffer. Will
On 07/11/18 21:59, Will Deacon wrote: > On Wed, Sep 26, 2018 at 02:56:23PM +0100, Julien Thierry wrote: >> When an EL2 entry of __kvm_hyp_vector is taken, it means an entry from a >> lower EL was previously taken to exit the guest. Taking that lower EL entry >> already applied vector hardening if needed, so there is no need to do it >> again. >> >> Only apply vector hardening for exception coming from lower EL. >> >> Signed-off-by: Julien Thierry <julien.thierry@arm.com> >> Cc: kvmarm@lists.cs.columbia.edu >> --- >> arch/arm64/kvm/hyp/hyp-entry.S | 17 ++++++++++++++--- >> 1 file changed, 14 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S >> index 24b4fba..da31386 100644 >> --- a/arch/arm64/kvm/hyp/hyp-entry.S >> +++ b/arch/arm64/kvm/hyp/hyp-entry.S >> @@ -257,7 +257,15 @@ ENTRY(__kvm_hyp_vector) >> ENDPROC(__kvm_hyp_vector) >> >> #ifdef CONFIG_KVM_INDIRECT_VECTORS >> -.macro hyp_ventry >> +.macro hyp_el2_ventry >> + .align 7 >> +1: b __kvm_hyp_vector + (1b - 0b) >> + .rept 31 >> + nop >> + .endr >> +.endm >> + >> +.macro hyp_el1_ventry >> .align 7 >> 1: .rept 27 >> nop >> @@ -290,8 +298,11 @@ alternative_cb_end > > I think it would be cleaner to take the EL as a macro parameter, but again, > I defer to Marc and Christoffer. I'd argue they don't have much in common here. Unless I put the branch for the el2 ventry after 27 nops like for the el1, we wouldn't gain much from putting the two in the same macro IMO. I'll see what Marc and Christoffer think about it. Thanks,
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index 24b4fba..da31386 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -257,7 +257,15 @@ ENTRY(__kvm_hyp_vector) ENDPROC(__kvm_hyp_vector) #ifdef CONFIG_KVM_INDIRECT_VECTORS -.macro hyp_ventry +.macro hyp_el2_ventry + .align 7 +1: b __kvm_hyp_vector + (1b - 0b) + .rept 31 + nop + .endr +.endm + +.macro hyp_el1_ventry .align 7 1: .rept 27 nop @@ -290,8 +298,11 @@ alternative_cb_end .macro generate_vectors 0: - .rept 16 - hyp_ventry + .rept 8 + hyp_el2_ventry + .endr + .rept 8 + hyp_el1_ventry .endr .org 0b + SZ_2K // Safety measure .endm
When an EL2 entry of __kvm_hyp_vector is taken, it means an entry from a lower EL was previously taken to exit the guest. Taking that lower EL entry already applied vector hardening if needed, so there is no need to do it again. Only apply vector hardening for exception coming from lower EL. Signed-off-by: Julien Thierry <julien.thierry@arm.com> Cc: kvmarm@lists.cs.columbia.edu --- arch/arm64/kvm/hyp/hyp-entry.S | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) -- 1.9.1