From 985bb51f17abbe83c697a5ac0aa40fad5f4e00f4 Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Thu, 28 Nov 2024 15:44:06 +0000 Subject: KVM: arm64: Always check the state from hyp_ack_unshare() There are multiple pKVM memory transitions where the state of a page is not cross-checked from the completer's PoV for performance reasons. For example, if a page is PKVM_PAGE_OWNED from the initiator's PoV, we should be guaranteed by construction that it is PKVM_NOPAGE for everybody else, hence allowing us to save a page-table lookup. When it was introduced, hyp_ack_unshare() followed that logic and bailed out without checking the PKVM_PAGE_SHARED_BORROWED state in the hypervisor's stage-1. This was correct as we could safely assume that all host-initiated shares were directed at the hypervisor at the time. But with the introduction of other types of shares (e.g. for FF-A or non-protected guests), it is now very much required to cross check this state to prevent the host from running __pkvm_host_unshare_hyp() on a page shared with TZ or a non-protected guest. Thankfully, if an attacker were to try this, the hyp_unmap() call from hyp_complete_unshare() would fail, hence causing to WARN() from __do_unshare() with the host lock held, which is fatal. But this is fragile at best, and can hardly be considered a security measure. Let's just do the right thing and always check the state from hyp_ack_unshare(). Signed-off-by: Quentin Perret Acked-by: Will Deacon Link: https://lore.kernel.org/r/20241128154406.602875-1-qperret@google.com Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch') diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index caba3e4bd09e..e75374d682f4 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -783,9 +783,6 @@ static int hyp_ack_unshare(u64 addr, const struct pkvm_mem_transition *tx) if (tx->initiator.id == PKVM_ID_HOST && hyp_page_count((void *)addr)) return -EBUSY; - if (__hyp_ack_skip_pgtable_check(tx)) - return 0; - return __hyp_check_page_state_range(addr, size, PKVM_PAGE_SHARED_BORROWED); } -- cgit v1.2.3 From e22c369520d0a2a191820cc308f81a860b1b8d47 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 17 Dec 2024 09:55:13 -0800 Subject: KVM: arm64: Add unified helper for reprogramming counters by mask Having separate helpers for enabling/disabling counters provides the wrong abstraction, as the state of each counter needs to be evaluated independently and, in some cases, use a different global enable bit. Collapse the enable/disable accessors into a single, common helper that reconfigures every counter set in @mask, leaving the complexity of determining if an event is actually enabled in kvm_pmu_counter_is_enabled(). Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20241217175513.3658056-1-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/pmu-emul.c | 66 +++++++++++++++++------------------------------ arch/arm64/kvm/sys_regs.c | 10 +++---- include/kvm/arm_pmu.h | 6 ++--- 3 files changed, 29 insertions(+), 53 deletions(-) (limited to 'arch') diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 456102bc0b55..6b3ec956a6e2 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -24,6 +24,7 @@ static DEFINE_MUTEX(arm_pmus_lock); static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc); static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc); +static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc); static struct kvm_vcpu *kvm_pmc_to_vcpu(const struct kvm_pmc *pmc) { @@ -327,48 +328,25 @@ u64 kvm_pmu_implemented_counter_mask(struct kvm_vcpu *vcpu) return GENMASK(val - 1, 0) | BIT(ARMV8_PMU_CYCLE_IDX); } -/** - * kvm_pmu_enable_counter_mask - enable selected PMU counters - * @vcpu: The vcpu pointer - * @val: the value guest writes to PMCNTENSET register - * - * Call perf_event_enable to start counting the perf event - */ -void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val) +static void kvm_pmc_enable_perf_event(struct kvm_pmc *pmc) { - int i; - if (!kvm_vcpu_has_pmu(vcpu)) - return; - - if (!(kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E) || !val) + if (!pmc->perf_event) { + kvm_pmu_create_perf_event(pmc); return; + } - for (i = 0; i < KVM_ARMV8_PMU_MAX_COUNTERS; i++) { - struct kvm_pmc *pmc; - - if (!(val & BIT(i))) - continue; - - pmc = kvm_vcpu_idx_to_pmc(vcpu, i); + perf_event_enable(pmc->perf_event); + if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE) + kvm_debug("fail to enable perf event\n"); +} - if (!pmc->perf_event) { - kvm_pmu_create_perf_event(pmc); - } else { - perf_event_enable(pmc->perf_event); - if (pmc->perf_event->state != PERF_EVENT_STATE_ACTIVE) - kvm_debug("fail to enable perf event\n"); - } - } +static void kvm_pmc_disable_perf_event(struct kvm_pmc *pmc) +{ + if (pmc->perf_event) + perf_event_disable(pmc->perf_event); } -/** - * kvm_pmu_disable_counter_mask - disable selected PMU counters - * @vcpu: The vcpu pointer - * @val: the value guest writes to PMCNTENCLR register - * - * Call perf_event_disable to stop counting the perf event - */ -void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val) +void kvm_pmu_reprogram_counter_mask(struct kvm_vcpu *vcpu, u64 val) { int i; @@ -376,16 +354,18 @@ void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val) return; for (i = 0; i < KVM_ARMV8_PMU_MAX_COUNTERS; i++) { - struct kvm_pmc *pmc; + struct kvm_pmc *pmc = kvm_vcpu_idx_to_pmc(vcpu, i); if (!(val & BIT(i))) continue; - pmc = kvm_vcpu_idx_to_pmc(vcpu, i); - - if (pmc->perf_event) - perf_event_disable(pmc->perf_event); + if (kvm_pmu_counter_is_enabled(pmc)) + kvm_pmc_enable_perf_event(pmc); + else + kvm_pmc_disable_perf_event(pmc); } + + kvm_vcpu_pmu_restore_guest(vcpu); } /* @@ -630,10 +610,10 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val) __vcpu_sys_reg(vcpu, PMCR_EL0) = val & ~(ARMV8_PMU_PMCR_C | ARMV8_PMU_PMCR_P); if (val & ARMV8_PMU_PMCR_E) { - kvm_pmu_enable_counter_mask(vcpu, + kvm_pmu_reprogram_counter_mask(vcpu, __vcpu_sys_reg(vcpu, PMCNTENSET_EL0)); } else { - kvm_pmu_disable_counter_mask(vcpu, + kvm_pmu_reprogram_counter_mask(vcpu, __vcpu_sys_reg(vcpu, PMCNTENSET_EL0)); } diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index e2a5c2918d9e..6ef8641d9833 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1208,16 +1208,14 @@ static bool access_pmcnten(struct kvm_vcpu *vcpu, struct sys_reg_params *p, mask = kvm_pmu_accessible_counter_mask(vcpu); if (p->is_write) { val = p->regval & mask; - if (r->Op2 & 0x1) { + if (r->Op2 & 0x1) /* accessing PMCNTENSET_EL0 */ __vcpu_sys_reg(vcpu, PMCNTENSET_EL0) |= val; - kvm_pmu_enable_counter_mask(vcpu, val); - kvm_vcpu_pmu_restore_guest(vcpu); - } else { + else /* accessing PMCNTENCLR_EL0 */ __vcpu_sys_reg(vcpu, PMCNTENSET_EL0) &= ~val; - kvm_pmu_disable_counter_mask(vcpu, val); - } + + kvm_pmu_reprogram_counter_mask(vcpu, val); } else { p->regval = __vcpu_sys_reg(vcpu, PMCNTENSET_EL0); } diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h index e61dd7dd2286..147bd3ee4f7b 100644 --- a/include/kvm/arm_pmu.h +++ b/include/kvm/arm_pmu.h @@ -53,8 +53,7 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1); void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu); void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu); void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu); -void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val); -void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val); +void kvm_pmu_reprogram_counter_mask(struct kvm_vcpu *vcpu, u64 val); void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu); void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu); bool kvm_pmu_should_notify_user(struct kvm_vcpu *vcpu); @@ -127,8 +126,7 @@ static inline u64 kvm_pmu_accessible_counter_mask(struct kvm_vcpu *vcpu) static inline void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu) {} static inline void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu) {} static inline void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu) {} -static inline void kvm_pmu_disable_counter_mask(struct kvm_vcpu *vcpu, u64 val) {} -static inline void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val) {} +static inline void kvm_pmu_reprogram_counter_mask(struct kvm_vcpu *vcpu, u64 val) {} static inline void kvm_pmu_flush_hwstate(struct kvm_vcpu *vcpu) {} static inline void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu) {} static inline bool kvm_pmu_should_notify_user(struct kvm_vcpu *vcpu) -- cgit v1.2.3 From adf8623b3f51e9c7eb18a7bb0381093f31053e38 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 17 Dec 2024 09:55:32 -0800 Subject: KVM: arm64: Use KVM_REQ_RELOAD_PMU to handle PMCR_EL0.E change Nested virt introduces yet another set of 'global' knobs for controlling event counters that are reserved for EL2 (i.e. >= HPMN). Get ready to share some plumbing with the NV controls by offloading counter reprogramming to KVM_REQ_RELOAD_PMU. Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20241217175532.3658134-1-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/pmu-emul.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) (limited to 'arch') diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 6b3ec956a6e2..c6423782a8aa 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -606,17 +606,13 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val) if (!kvm_has_feat(vcpu->kvm, ID_AA64DFR0_EL1, PMUVer, V3P5)) val &= ~ARMV8_PMU_PMCR_LP; + /* Request a reload of the PMU to enable/disable affected counters */ + if ((__vcpu_sys_reg(vcpu, PMCR_EL0) ^ val) & ARMV8_PMU_PMCR_E) + kvm_make_request(KVM_REQ_RELOAD_PMU, vcpu); + /* The reset bits don't indicate any state, and shouldn't be saved. */ __vcpu_sys_reg(vcpu, PMCR_EL0) = val & ~(ARMV8_PMU_PMCR_C | ARMV8_PMU_PMCR_P); - if (val & ARMV8_PMU_PMCR_E) { - kvm_pmu_reprogram_counter_mask(vcpu, - __vcpu_sys_reg(vcpu, PMCNTENSET_EL0)); - } else { - kvm_pmu_reprogram_counter_mask(vcpu, - __vcpu_sys_reg(vcpu, PMCNTENSET_EL0)); - } - if (val & ARMV8_PMU_PMCR_C) kvm_pmu_set_counter_value(vcpu, ARMV8_PMU_CYCLE_IDX, 0); @@ -626,7 +622,6 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val) for_each_set_bit(i, &mask, 32) kvm_pmu_set_pmc_value(kvm_vcpu_idx_to_pmc(vcpu, i), 0, true); } - kvm_vcpu_pmu_restore_guest(vcpu); } static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc) @@ -890,11 +885,11 @@ void kvm_vcpu_reload_pmu(struct kvm_vcpu *vcpu) { u64 mask = kvm_pmu_implemented_counter_mask(vcpu); - kvm_pmu_handle_pmcr(vcpu, kvm_vcpu_read_pmcr(vcpu)); - __vcpu_sys_reg(vcpu, PMOVSSET_EL0) &= mask; __vcpu_sys_reg(vcpu, PMINTENSET_EL1) &= mask; __vcpu_sys_reg(vcpu, PMCNTENSET_EL0) &= mask; + + kvm_pmu_reprogram_counter_mask(vcpu, mask); } int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu) -- cgit v1.2.3 From d3ba35b69eaed060bbc92a99bf027627bad170eb Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 17 Dec 2024 09:55:50 -0800 Subject: KVM: arm64: nv: Reload PMU events upon MDCR_EL2.HPME change MDCR_EL2.HPME is the 'global' enable bit for event counters reserved for EL2. Give the PMU a kick when it's changed to ensure events are reprogrammed before returning to the guest. Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20241217175550.3658212-1-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/sys_regs.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 6ef8641d9833..634ff18a59a1 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2448,6 +2448,26 @@ static unsigned int s1pie_el2_visibility(const struct kvm_vcpu *vcpu, return __el2_visibility(vcpu, rd, s1pie_visibility); } +static bool access_mdcr(struct kvm_vcpu *vcpu, + struct sys_reg_params *p, + const struct sys_reg_desc *r) +{ + u64 old = __vcpu_sys_reg(vcpu, MDCR_EL2); + + if (!access_rw(vcpu, p, r)) + return false; + + /* + * Request a reload of the PMU to enable/disable the counters affected + * by HPME. + */ + if ((old ^ __vcpu_sys_reg(vcpu, MDCR_EL2)) & MDCR_EL2_HPME) + kvm_make_request(KVM_REQ_RELOAD_PMU, vcpu); + + return true; +} + + /* * Architected system registers. * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2 @@ -2981,7 +3001,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { EL2_REG(SCTLR_EL2, access_rw, reset_val, SCTLR_EL2_RES1), EL2_REG(ACTLR_EL2, access_rw, reset_val, 0), EL2_REG_VNCR(HCR_EL2, reset_hcr, 0), - EL2_REG(MDCR_EL2, access_rw, reset_val, 0), + EL2_REG(MDCR_EL2, access_mdcr, reset_val, 0), EL2_REG(CPTR_EL2, access_rw, reset_val, CPTR_NVHE_EL2_RES1), EL2_REG_VNCR(HSTR_EL2, reset_val, 0), EL2_REG_VNCR(HFGRTR_EL2, reset_val, 0), -- cgit v1.2.3 From e96d8b80afd3f63ffad58c0fdd5e0c380c4c404e Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Tue, 17 Dec 2024 09:56:11 -0800 Subject: KVM: arm64: Only apply PMCR_EL0.P to the guest range of counters An important distinction from other registers affected by HPMN is that PMCR_EL0 only affects the guest range of counters, regardless of the EL from which it is accessed. Ensure that PMCR_EL0.P is always applied to 'guest' counters by manually computing the mask rather than deriving it from the current context. Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20241217175611.3658290-1-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/pmu-emul.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index c6423782a8aa..6c5950b9ceac 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -617,8 +617,14 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val) kvm_pmu_set_counter_value(vcpu, ARMV8_PMU_CYCLE_IDX, 0); if (val & ARMV8_PMU_PMCR_P) { - unsigned long mask = kvm_pmu_accessible_counter_mask(vcpu); - mask &= ~BIT(ARMV8_PMU_CYCLE_IDX); + /* + * Unlike other PMU sysregs, the controls in PMCR_EL0 always apply + * to the 'guest' range of counters and never the 'hyp' range. + */ + unsigned long mask = kvm_pmu_implemented_counter_mask(vcpu) & + ~kvm_pmu_hyp_counter_mask(vcpu) & + ~BIT(ARMV8_PMU_CYCLE_IDX); + for_each_set_bit(i, &mask, 32) kvm_pmu_set_pmc_value(kvm_vcpu_idx_to_pmc(vcpu, i), 0, true); } -- cgit v1.2.3