From 3579dc742f76207a4854a87a8e3ce44434d7e308 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 28 Aug 2023 15:46:49 +0100 Subject: [PATCH 1/2] KVM: arm64: Properly return allocated EL2 VA from hyp_alloc_private_va_range() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Marek reports that his RPi4 spits out a warning at boot time, right at the point where the GICv2 virtual CPU interface gets mapped. Upon investigation, it seems that we never return the allocated VA and use whatever was on the stack at this point. Yes, this is good stuff, and Marek was pretty lucky that he ended-up with a VA that intersected with something that was already mapped. On my setup, this random value is plausible enough for the mapping to take place. Who knows what happens... Fixes: f156a7d13fc3 ("KVM: arm64: Remove size-order align in the nVHE hyp private VA range") Reported-by: Marek Szyprowski Tested-by: Marek Szyprowski Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Vincent Donnefort Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/79b0ad6e-0c2a-f777-d504-e40e8123d81d@samsung.com Link: https://lore.kernel.org/r/20230828153121.4179627-1-maz@kernel.org --- arch/arm64/kvm/mmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 587a104f66c371..482280fe22d7c5 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -652,6 +652,9 @@ int hyp_alloc_private_va_range(size_t size, unsigned long *haddr) mutex_unlock(&kvm_hyp_pgd_mutex); + if (!ret) + *haddr = base; + return ret; } From 373beef00f7d781a000b12c31fb17a5a9c25969c Mon Sep 17 00:00:00 2001 From: Jean-Philippe Brucker Date: Mon, 11 Sep 2023 15:52:57 +0100 Subject: [PATCH 2/2] KVM: arm64: nvhe: Ignore SVE hint in SMCCC function ID When SVE is enabled, the host may set bit 16 in SMCCC function IDs, a hint that indicates an unused SVE state. At the moment NVHE doesn't account for this bit when inspecting the function ID, and rejects most calls. Clear the hint bit before comparing function IDs. About version compatibility: the host's PSCI driver initially probes the firmware for a SMCCC version number. If the firmware implements a protocol recent enough (1.3), subsequent SMCCC calls have the hint bit set. Since the hint bit was reserved in earlier versions of the protocol, clearing it is fine regardless of the version in use. When a new hint is added to the protocol in the future, it will be added to ARM_SMCCC_CALL_HINTS and NVHE will handle it straight away. This patch only clears known hints and leaves reserved bits as is, because future SMCCC versions could use reserved bits as modifiers for the function ID, rather than hints. Fixes: cfa7ff959a78 ("arm64: smccc: Support SMCCC v1.3 SVE register saving hint") Reported-by: Ben Horgan Signed-off-by: Jean-Philippe Brucker Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230911145254.934414-4-jean-philippe@linaro.org --- arch/arm64/include/asm/kvm_hyp.h | 2 +- arch/arm64/kvm/hyp/include/nvhe/ffa.h | 2 +- arch/arm64/kvm/hyp/nvhe/ffa.c | 3 +-- arch/arm64/kvm/hyp/nvhe/hyp-init.S | 1 + arch/arm64/kvm/hyp/nvhe/hyp-main.c | 8 ++++++-- arch/arm64/kvm/hyp/nvhe/psci-relay.c | 3 +-- include/linux/arm-smccc.h | 2 ++ 7 files changed, 13 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index b7238c72a04cfa..66efd67ea7e8d6 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -118,7 +118,7 @@ void deactivate_traps_vhe_put(struct kvm_vcpu *vcpu); u64 __guest_enter(struct kvm_vcpu *vcpu); -bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt); +bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt, u32 func_id); #ifdef __KVM_NVHE_HYPERVISOR__ void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr, diff --git a/arch/arm64/kvm/hyp/include/nvhe/ffa.h b/arch/arm64/kvm/hyp/include/nvhe/ffa.h index 1becb10ecd8057..d9fd5e6c7d3cca 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/ffa.h +++ b/arch/arm64/kvm/hyp/include/nvhe/ffa.h @@ -12,6 +12,6 @@ #define FFA_MAX_FUNC_NUM 0x7F int hyp_ffa_init(void *pages); -bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt); +bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id); #endif /* __KVM_HYP_FFA_H */ diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c index ab4f5d160c58f9..6e4dba9eadef52 100644 --- a/arch/arm64/kvm/hyp/nvhe/ffa.c +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c @@ -634,9 +634,8 @@ static bool do_ffa_features(struct arm_smccc_res *res, return true; } -bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt) +bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id) { - DECLARE_REG(u64, func_id, host_ctxt, 0); struct arm_smccc_res res; /* diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S index 90fade1b032e4b..1cc06e6797bda3 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S @@ -57,6 +57,7 @@ __do_hyp_init: cmp x0, #HVC_STUB_HCALL_NR b.lo __kvm_handle_stub_hvc + bic x0, x0, #ARM_SMCCC_CALL_HINTS mov x3, #KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) cmp x0, x3 b.eq 1f diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 857d9bc04fd48a..2385fd03ed87c6 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -368,6 +368,7 @@ static void handle_host_hcall(struct kvm_cpu_context *host_ctxt) if (static_branch_unlikely(&kvm_protected_mode_initialized)) hcall_min = __KVM_HOST_SMCCC_FUNC___pkvm_prot_finalize; + id &= ~ARM_SMCCC_CALL_HINTS; id -= KVM_HOST_SMCCC_ID(0); if (unlikely(id < hcall_min || id >= ARRAY_SIZE(host_hcall))) @@ -392,11 +393,14 @@ static void default_host_smc_handler(struct kvm_cpu_context *host_ctxt) static void handle_host_smc(struct kvm_cpu_context *host_ctxt) { + DECLARE_REG(u64, func_id, host_ctxt, 0); bool handled; - handled = kvm_host_psci_handler(host_ctxt); + func_id &= ~ARM_SMCCC_CALL_HINTS; + + handled = kvm_host_psci_handler(host_ctxt, func_id); if (!handled) - handled = kvm_host_ffa_handler(host_ctxt); + handled = kvm_host_ffa_handler(host_ctxt, func_id); if (!handled) default_host_smc_handler(host_ctxt); diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c index 24543d2a34905c..d57bcb6ab94d25 100644 --- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c +++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c @@ -273,9 +273,8 @@ static unsigned long psci_1_0_handler(u64 func_id, struct kvm_cpu_context *host_ } } -bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt) +bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt, u32 func_id) { - DECLARE_REG(u64, func_id, host_ctxt, 0); unsigned long ret; switch (kvm_host_psci_config.version) { diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h index 7c67c17321d4ca..083f8565371616 100644 --- a/include/linux/arm-smccc.h +++ b/include/linux/arm-smccc.h @@ -67,6 +67,8 @@ #define ARM_SMCCC_VERSION_1_3 0x10003 #define ARM_SMCCC_1_3_SVE_HINT 0x10000 +#define ARM_SMCCC_CALL_HINTS ARM_SMCCC_1_3_SVE_HINT + #define ARM_SMCCC_VERSION_FUNC_ID \ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \