| Message ID | 20240822-kvm-arm64-hide-pie-regs-v2-2-376624fa829c@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Control visibility of S1PIE related sysregs to userspace | expand |
On Thu, 22 Aug 2024 00:35:37 +0100, Mark Brown <broonie@kernel.org> wrote: > > When the guest does not support FEAT_TCR2 we should not allow any access > to it in order to ensure that we do not create spurious issues with guest > migration. Add a visibility operation for it. > > Fixes: fbff56068232 ("KVM: arm64: Save/restore TCR2_EL1") > Signed-off-by: Mark Brown <broonie@kernel.org> > --- > arch/arm64/include/asm/kvm_host.h | 3 +++ > arch/arm64/kvm/sys_regs.c | 29 ++++++++++++++++++++++++++--- > 2 files changed, 29 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index ab4c675b491d..7889e5f4009f 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -1476,4 +1476,7 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val); > (pa + pi + pa3) == 1; \ > }) > > +#define kvm_has_tcr2(k) \ > + (kvm_has_feat((k), ID_AA64MMFR3_EL1, TCRX, IMP)) > + > #endif /* __ARM64_KVM_HOST_H__ */ > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 1af15140e067..6d5f43781042 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -2319,6 +2319,27 @@ static bool access_zcr_el2(struct kvm_vcpu *vcpu, > return true; > } > > +static unsigned int tcr2_visibility(const struct kvm_vcpu *vcpu, > + const struct sys_reg_desc *rd) > +{ > + if (kvm_has_tcr2(vcpu->kvm)) > + return 0; > + > + return REG_HIDDEN; > +} > + > +static unsigned int tcr2_el2_visibility(const struct kvm_vcpu *vcpu, > + const struct sys_reg_desc *rd) > +{ > + unsigned int r; > + > + r = el2_visibility(vcpu, rd); > + if (r) > + return r; > + > + return tcr2_visibility(vcpu, rd); > +} > + > /* > * Architected system registers. > * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2 > @@ -2503,7 +2524,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { > { SYS_DESC(SYS_TTBR0_EL1), access_vm_reg, reset_unknown, TTBR0_EL1 }, > { SYS_DESC(SYS_TTBR1_EL1), access_vm_reg, reset_unknown, TTBR1_EL1 }, > { SYS_DESC(SYS_TCR_EL1), access_vm_reg, reset_val, TCR_EL1, 0 }, > - { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0 }, > + { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0, > + .visibility = tcr2_visibility }, With this, we should be able to simplify the accessor, shouldn't we? > > PTRAUTH_KEY(APIA), > PTRAUTH_KEY(APIB), > @@ -2820,7 +2842,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { > EL2_REG(TTBR0_EL2, access_rw, reset_val, 0), > EL2_REG(TTBR1_EL2, access_rw, reset_val, 0), > EL2_REG(TCR_EL2, access_rw, reset_val, TCR_EL2_RES1), > - EL2_REG(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1), > + EL2_REG_FILTERED(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1, > + tcr2_el2_visibility), Same thing here. Thanks, M.
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index ab4c675b491d..7889e5f4009f 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1476,4 +1476,7 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val); (pa + pi + pa3) == 1; \ }) +#define kvm_has_tcr2(k) \ + (kvm_has_feat((k), ID_AA64MMFR3_EL1, TCRX, IMP)) + #endif /* __ARM64_KVM_HOST_H__ */ diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 1af15140e067..6d5f43781042 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2319,6 +2319,27 @@ static bool access_zcr_el2(struct kvm_vcpu *vcpu, return true; } +static unsigned int tcr2_visibility(const struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd) +{ + if (kvm_has_tcr2(vcpu->kvm)) + return 0; + + return REG_HIDDEN; +} + +static unsigned int tcr2_el2_visibility(const struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd) +{ + unsigned int r; + + r = el2_visibility(vcpu, rd); + if (r) + return r; + + return tcr2_visibility(vcpu, rd); +} + /* * Architected system registers. * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2 @@ -2503,7 +2524,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_TTBR0_EL1), access_vm_reg, reset_unknown, TTBR0_EL1 }, { SYS_DESC(SYS_TTBR1_EL1), access_vm_reg, reset_unknown, TTBR1_EL1 }, { SYS_DESC(SYS_TCR_EL1), access_vm_reg, reset_val, TCR_EL1, 0 }, - { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0 }, + { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0, + .visibility = tcr2_visibility }, PTRAUTH_KEY(APIA), PTRAUTH_KEY(APIB), @@ -2820,7 +2842,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { EL2_REG(TTBR0_EL2, access_rw, reset_val, 0), EL2_REG(TTBR1_EL2, access_rw, reset_val, 0), EL2_REG(TCR_EL2, access_rw, reset_val, TCR_EL2_RES1), - EL2_REG(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1), + EL2_REG_FILTERED(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1, + tcr2_el2_visibility), EL2_REG_VNCR(VTTBR_EL2, reset_val, 0), EL2_REG_VNCR(VTCR_EL2, reset_val, 0), @@ -4626,7 +4649,7 @@ void kvm_calculate_traps(struct kvm_vcpu *vcpu) if (kvm_has_feat(kvm, ID_AA64ISAR2_EL1, MOPS, IMP)) vcpu->arch.hcrx_el2 |= (HCRX_EL2_MSCEn | HCRX_EL2_MCE2); - if (kvm_has_feat(kvm, ID_AA64MMFR3_EL1, TCRX, IMP)) + if (kvm_has_tcr2(kvm)) vcpu->arch.hcrx_el2 |= HCRX_EL2_TCR2En; }
When the guest does not support FEAT_TCR2 we should not allow any access to it in order to ensure that we do not create spurious issues with guest migration. Add a visibility operation for it. Fixes: fbff56068232 ("KVM: arm64: Save/restore TCR2_EL1") Signed-off-by: Mark Brown <broonie@kernel.org> --- arch/arm64/include/asm/kvm_host.h | 3 +++ arch/arm64/kvm/sys_regs.c | 29 ++++++++++++++++++++++++++--- 2 files changed, 29 insertions(+), 3 deletions(-)