[v4,13/40] KVM: arm64: Introduce VHE-specific kvm_vcpu_run
diff mbox

Message ID 20180215210332.8648-14-christoffer.dall@linaro.org
State New
Headers show

Commit Message

Christoffer Dall Feb. 15, 2018, 9:03 p.m. UTC
So far this is mostly (see below) a copy of the legacy non-VHE switch
function, but we will start reworking these functions in separate
directions to work on VHE and non-VHE in the most optimal way in later
patches.

The only difference after this patch between the VHE and non-VHE run
functions is that we omit the branch-predictor variant-2 hardening for
QC Falkor CPUs, because this workaround is specific to a series of
non-VHE ARMv8.0 CPUs.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---

Notes:
    Changes since v3:
     - Added BUG() to 32-bit ARM VHE run function
     - Omitted QC Falkor BP Hardening functionality from VHE-specific
       function
    
    Changes since v2:
     - Reworded commit message
    
    Changes since v1:
     - Rename kvm_vcpu_run to kvm_vcpu_run_vhe and rename __kvm_vcpu_run to
       __kvm_vcpu_run_nvhe
     - Removed stray whitespace line

 arch/arm/include/asm/kvm_asm.h   |  5 ++-
 arch/arm/kvm/hyp/switch.c        |  2 +-
 arch/arm64/include/asm/kvm_asm.h |  4 ++-
 arch/arm64/kvm/hyp/switch.c      | 66 +++++++++++++++++++++++++++++++++++++++-
 virt/kvm/arm/arm.c               |  5 ++-
 5 files changed, 77 insertions(+), 5 deletions(-)

Comments

Andrew Jones Feb. 21, 2018, 5:43 p.m. UTC | #1
On Thu, Feb 15, 2018 at 10:03:05PM +0100, Christoffer Dall wrote:
> So far this is mostly (see below) a copy of the legacy non-VHE switch
> function, but we will start reworking these functions in separate
> directions to work on VHE and non-VHE in the most optimal way in later
> patches.
> 
> The only difference after this patch between the VHE and non-VHE run
> functions is that we omit the branch-predictor variant-2 hardening for
> QC Falkor CPUs, because this workaround is specific to a series of
> non-VHE ARMv8.0 CPUs.
> 
> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
> ---
> 
> Notes:
>     Changes since v3:
>      - Added BUG() to 32-bit ARM VHE run function
>      - Omitted QC Falkor BP Hardening functionality from VHE-specific
>        function
>     
>     Changes since v2:
>      - Reworded commit message
>     
>     Changes since v1:
>      - Rename kvm_vcpu_run to kvm_vcpu_run_vhe and rename __kvm_vcpu_run to
>        __kvm_vcpu_run_nvhe
>      - Removed stray whitespace line
> 
>  arch/arm/include/asm/kvm_asm.h   |  5 ++-
>  arch/arm/kvm/hyp/switch.c        |  2 +-
>  arch/arm64/include/asm/kvm_asm.h |  4 ++-
>  arch/arm64/kvm/hyp/switch.c      | 66 +++++++++++++++++++++++++++++++++++++++-
>  virt/kvm/arm/arm.c               |  5 ++-
>  5 files changed, 77 insertions(+), 5 deletions(-)
> 

...

> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 2062d9357971..5bd879c78951 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -736,7 +736,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  		if (has_vhe())
>  			kvm_arm_vhe_guest_enter();
>  
> -		ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);
> +		if (has_vhe())
> +			ret = kvm_vcpu_run_vhe(vcpu);
> +		else
> +			ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);
>  
>  		if (has_vhe())
>  			kvm_arm_vhe_guest_exit();

We can combine these has_vhe()'s

 if (has_vhe()) {
    kvm_arm_vhe_guest_enter();
    ret = kvm_vcpu_run_vhe(vcpu);
    kvm_arm_vhe_guest_exit();
 } else
    ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);

Thanks,
drew
Andrew Jones Feb. 21, 2018, 6:18 p.m. UTC | #2
On Wed, Feb 21, 2018 at 06:43:00PM +0100, Andrew Jones wrote:
> On Thu, Feb 15, 2018 at 10:03:05PM +0100, Christoffer Dall wrote:
> > So far this is mostly (see below) a copy of the legacy non-VHE switch
> > function, but we will start reworking these functions in separate
> > directions to work on VHE and non-VHE in the most optimal way in later
> > patches.
> > 
> > The only difference after this patch between the VHE and non-VHE run
> > functions is that we omit the branch-predictor variant-2 hardening for
> > QC Falkor CPUs, because this workaround is specific to a series of
> > non-VHE ARMv8.0 CPUs.
> > 
> > Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
> > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
> > ---
> > 
> > Notes:
> >     Changes since v3:
> >      - Added BUG() to 32-bit ARM VHE run function
> >      - Omitted QC Falkor BP Hardening functionality from VHE-specific
> >        function
> >     
> >     Changes since v2:
> >      - Reworded commit message
> >     
> >     Changes since v1:
> >      - Rename kvm_vcpu_run to kvm_vcpu_run_vhe and rename __kvm_vcpu_run to
> >        __kvm_vcpu_run_nvhe
> >      - Removed stray whitespace line
> > 
> >  arch/arm/include/asm/kvm_asm.h   |  5 ++-
> >  arch/arm/kvm/hyp/switch.c        |  2 +-
> >  arch/arm64/include/asm/kvm_asm.h |  4 ++-
> >  arch/arm64/kvm/hyp/switch.c      | 66 +++++++++++++++++++++++++++++++++++++++-
> >  virt/kvm/arm/arm.c               |  5 ++-
> >  5 files changed, 77 insertions(+), 5 deletions(-)
> > 
> 
> ...
> 
> > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> > index 2062d9357971..5bd879c78951 100644
> > --- a/virt/kvm/arm/arm.c
> > +++ b/virt/kvm/arm/arm.c
> > @@ -736,7 +736,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
> >  		if (has_vhe())
> >  			kvm_arm_vhe_guest_enter();
> >  
> > -		ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);
> > +		if (has_vhe())
> > +			ret = kvm_vcpu_run_vhe(vcpu);
> > +		else
> > +			ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);
> >  
> >  		if (has_vhe())
> >  			kvm_arm_vhe_guest_exit();
> 
> We can combine these has_vhe()'s
> 
>  if (has_vhe()) {
>     kvm_arm_vhe_guest_enter();
>     ret = kvm_vcpu_run_vhe(vcpu);
>     kvm_arm_vhe_guest_exit();
>  } else
>     ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);

Maybe even do a cleanup patch that removes
kvm_arm_vhe_guest_enter/exit by putting the daif
masking/restoring directly into kvm_vcpu_run_vhe()?

Thanks,
drew
Christoffer Dall Feb. 22, 2018, 9:16 a.m. UTC | #3
On Wed, Feb 21, 2018 at 07:18:32PM +0100, Andrew Jones wrote:
> On Wed, Feb 21, 2018 at 06:43:00PM +0100, Andrew Jones wrote:
> > On Thu, Feb 15, 2018 at 10:03:05PM +0100, Christoffer Dall wrote:
> > > So far this is mostly (see below) a copy of the legacy non-VHE switch
> > > function, but we will start reworking these functions in separate
> > > directions to work on VHE and non-VHE in the most optimal way in later
> > > patches.
> > > 
> > > The only difference after this patch between the VHE and non-VHE run
> > > functions is that we omit the branch-predictor variant-2 hardening for
> > > QC Falkor CPUs, because this workaround is specific to a series of
> > > non-VHE ARMv8.0 CPUs.
> > > 
> > > Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
> > > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
> > > ---
> > > 
> > > Notes:
> > >     Changes since v3:
> > >      - Added BUG() to 32-bit ARM VHE run function
> > >      - Omitted QC Falkor BP Hardening functionality from VHE-specific
> > >        function
> > >     
> > >     Changes since v2:
> > >      - Reworded commit message
> > >     
> > >     Changes since v1:
> > >      - Rename kvm_vcpu_run to kvm_vcpu_run_vhe and rename __kvm_vcpu_run to
> > >        __kvm_vcpu_run_nvhe
> > >      - Removed stray whitespace line
> > > 
> > >  arch/arm/include/asm/kvm_asm.h   |  5 ++-
> > >  arch/arm/kvm/hyp/switch.c        |  2 +-
> > >  arch/arm64/include/asm/kvm_asm.h |  4 ++-
> > >  arch/arm64/kvm/hyp/switch.c      | 66 +++++++++++++++++++++++++++++++++++++++-
> > >  virt/kvm/arm/arm.c               |  5 ++-
> > >  5 files changed, 77 insertions(+), 5 deletions(-)
> > > 
> > 
> > ...
> > 
> > > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> > > index 2062d9357971..5bd879c78951 100644
> > > --- a/virt/kvm/arm/arm.c
> > > +++ b/virt/kvm/arm/arm.c
> > > @@ -736,7 +736,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
> > >  		if (has_vhe())
> > >  			kvm_arm_vhe_guest_enter();
> > >  
> > > -		ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);
> > > +		if (has_vhe())
> > > +			ret = kvm_vcpu_run_vhe(vcpu);
> > > +		else
> > > +			ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);
> > >  
> > >  		if (has_vhe())
> > >  			kvm_arm_vhe_guest_exit();
> > 
> > We can combine these has_vhe()'s
> > 
> >  if (has_vhe()) {
> >     kvm_arm_vhe_guest_enter();
> >     ret = kvm_vcpu_run_vhe(vcpu);
> >     kvm_arm_vhe_guest_exit();
> >  } else
> >     ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);
> 
> Maybe even do a cleanup patch that removes
> kvm_arm_vhe_guest_enter/exit by putting the daif
> masking/restoring directly into kvm_vcpu_run_vhe()?
> 
Yes, indeed.  This is a blind rebasing result on my part.

Thanks,
-Christoffer

Patch
diff mbox

diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 36dd2962a42d..5a953ecb0d78 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -70,7 +70,10 @@  extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);
 
 extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);
 
-extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
+/* no VHE on 32-bit :( */
+static inline int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) { BUG(); return 0; }
+
+extern int __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu);
 
 extern void __init_stage2_translation(void);
 
diff --git a/arch/arm/kvm/hyp/switch.c b/arch/arm/kvm/hyp/switch.c
index e86679daddff..aac025783ee8 100644
--- a/arch/arm/kvm/hyp/switch.c
+++ b/arch/arm/kvm/hyp/switch.c
@@ -154,7 +154,7 @@  static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
 	return true;
 }
 
-int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
+int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 6b626750b0a1..0be2747a6c5f 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -58,7 +58,9 @@  extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);
 
 extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);
 
-extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
+extern int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu);
+
+extern int __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu);
 
 extern u64 __vgic_v3_get_ich_vtr_el2(void);
 extern u64 __vgic_v3_read_vmcr(void);
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index d2c0b1ae3216..b6126af539b6 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -362,7 +362,71 @@  static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
 	return false;
 }
 
-int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
+/* Switch to the guest for VHE systems running in EL2 */
+int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpu_context *host_ctxt;
+	struct kvm_cpu_context *guest_ctxt;
+	bool fp_enabled;
+	u64 exit_code;
+
+	vcpu = kern_hyp_va(vcpu);
+
+	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
+	host_ctxt->__hyp_running_vcpu = vcpu;
+	guest_ctxt = &vcpu->arch.ctxt;
+
+	__sysreg_save_host_state(host_ctxt);
+
+	__activate_traps(vcpu);
+	__activate_vm(vcpu);
+
+	__vgic_restore_state(vcpu);
+	__timer_enable_traps(vcpu);
+
+	/*
+	 * We must restore the 32-bit state before the sysregs, thanks
+	 * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
+	 */
+	__sysreg32_restore_state(vcpu);
+	__sysreg_restore_guest_state(guest_ctxt);
+	__debug_switch_to_guest(vcpu);
+
+	do {
+		/* Jump in the fire! */
+		exit_code = __guest_enter(vcpu, host_ctxt);
+
+		/* And we're baaack! */
+	} while (fixup_guest_exit(vcpu, &exit_code));
+
+	fp_enabled = __fpsimd_enabled();
+
+	__sysreg_save_guest_state(guest_ctxt);
+	__sysreg32_save_state(vcpu);
+	__timer_disable_traps(vcpu);
+	__vgic_save_state(vcpu);
+
+	__deactivate_traps(vcpu);
+	__deactivate_vm(vcpu);
+
+	__sysreg_restore_host_state(host_ctxt);
+
+	if (fp_enabled) {
+		__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
+		__fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
+	}
+
+	/*
+	 * This must come after restoring the host sysregs, since a non-VHE
+	 * system may enable SPE here and make use of the TTBRs.
+	 */
+	__debug_switch_to_host(vcpu);
+
+	return exit_code;
+}
+
+/* Switch to the guest for legacy non-VHE systems */
+int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 2062d9357971..5bd879c78951 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -736,7 +736,10 @@  int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		if (has_vhe())
 			kvm_arm_vhe_guest_enter();
 
-		ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);
+		if (has_vhe())
+			ret = kvm_vcpu_run_vhe(vcpu);
+		else
+			ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);
 
 		if (has_vhe())
 			kvm_arm_vhe_guest_exit();