diff options
| author | Will Deacon <will.deacon@arm.com> | 2016-09-22 11:35:43 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2017-02-02 18:33:01 +0000 |
| commit | f85279b4bd481a1a0697c1d2a8a5f15de216b120 (patch) | |
| tree | 85ae5ff3b6cfae4ea9ef703d31cfd0a2e46e9983 /arch/arm64/kvm/hyp/switch.c | |
| parent | 3d29a9a0f88300b7ccb642ebee61b331ef0a8c27 (diff) | |
arm64: KVM: Save/restore the host SPE state when entering/leaving a VM
The SPE buffer is virtually addressed, using the page tables of the CPU
MMU. Unusually, this means that the EL0/1 page table may be live whilst
we're executing at EL2 on non-VHE configurations. When VHE is in use,
we can use the same property to profile the guest behind its back.
This patch adds the relevant disabling and flushing code to KVM so that
the host can make use of SPE without corrupting guest memory, and any
attempts by a guest to use SPE will result in a trap.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alex Bennée <alex.bennee@linaro.org>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kvm/hyp/switch.c')
| -rw-r--r-- | arch/arm64/kvm/hyp/switch.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 75e83dd40d43..aede1658aeda 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -103,7 +103,13 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) static void __hyp_text __deactivate_traps_vhe(void) { extern char vectors[]; /* kernel exception vectors */ + u64 mdcr_el2 = read_sysreg(mdcr_el2); + mdcr_el2 &= MDCR_EL2_HPMN_MASK | + MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT | + MDCR_EL2_TPMS; + + write_sysreg(mdcr_el2, mdcr_el2); write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); write_sysreg(CPACR_EL1_FPEN, cpacr_el1); write_sysreg(vectors, vbar_el1); @@ -111,6 +117,12 @@ static void __hyp_text __deactivate_traps_vhe(void) static void __hyp_text __deactivate_traps_nvhe(void) { + u64 mdcr_el2 = read_sysreg(mdcr_el2); + + mdcr_el2 &= MDCR_EL2_HPMN_MASK; + mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT; + + write_sysreg(mdcr_el2, mdcr_el2); write_sysreg(HCR_RW, hcr_el2); write_sysreg(CPTR_EL2_DEFAULT, cptr_el2); } @@ -132,7 +144,6 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) __deactivate_traps_arch()(); write_sysreg(0, hstr_el2); - write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2); write_sysreg(0, pmuserenr_el0); } @@ -357,6 +368,10 @@ again: } __debug_save_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt); + /* + * This must come after restoring the host sysregs, since a non-VHE + * system may enable SPE here and make use of the TTBRs. + */ __debug_cond_restore_host_state(vcpu); return exit_code; |