From: Marc Zyngier <marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com> Subject: [PATCH 18/18] KVM: arm/arm64: Move HYP IO VAs to the "idmap" range Date: Wed, 6 Dec 2017 14:38:39 +0000 [thread overview] Message-ID: <20171206143839.29223-19-marc.zyngier@arm.com> (raw) In-Reply-To: <20171206143839.29223-1-marc.zyngier@arm.com> We so far mapped our HYP IO (which is essencially the GICv2 control registers) using the same method as for memory. It recently appeared that is a bit unsafe: we compute the HYP VA using the kern_hyp_va helper, but that helper is only designed to deal with kernel VAs coming from the linear map, and not from the vmalloc region... This could in turn cause some bad aliasing between the two, amplified by the new VA randomisation. A solution is to come up with our very own basic VA allocator for MMIO. Since half of the HYP address space only contains a single page (the idmap), we have plenty to borrow from. Let's use the idmap as a base, and allocate downwards from it. GICv2 now lives on the other side of the great VA barrier. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/mmu.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 9f73a8a17147..d843548abd3d 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -43,6 +43,9 @@ static unsigned long hyp_idmap_start; static unsigned long hyp_idmap_end; static phys_addr_t hyp_idmap_vector; +static DEFINE_MUTEX(io_map_lock); +static unsigned long io_map_base; + #define S2_PGD_SIZE (PTRS_PER_S2_PGD * sizeof(pgd_t)) #define hyp_pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t)) @@ -723,7 +726,8 @@ int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size, void __iomem **kaddr, void __iomem **haddr) { - unsigned long start, end; + pgd_t *pgd = hyp_pgd; + unsigned long base; int ret; *kaddr = ioremap(phys_addr, size); @@ -735,19 +739,26 @@ int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size, return 0; } + mutex_lock(&io_map_lock); + + base = io_map_base - size; + base &= ~(size - 1); + + if (__kvm_cpu_uses_extended_idmap()) + pgd = boot_hyp_pgd; - start = kern_hyp_va((unsigned long)*kaddr); - end = kern_hyp_va((unsigned long)*kaddr + size); - ret = __create_hyp_mappings(hyp_pgd, start, end, + ret = __create_hyp_mappings(pgd, base, base + size, __phys_to_pfn(phys_addr), PAGE_HYP_DEVICE); if (ret) { iounmap(*kaddr); *kaddr = NULL; } else { - *haddr = (void __iomem *)start; + *haddr = (void __iomem *)base; + io_map_base = base; } + mutex_unlock(&io_map_lock); return ret; } @@ -1828,6 +1839,7 @@ int kvm_mmu_init(void) goto out; } + io_map_base = hyp_idmap_start; return 0; out: free_hyp_pgds(); -- 2.14.2
WARNING: multiple messages have this Message-ID (diff)
From: marc.zyngier@arm.com (Marc Zyngier) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 18/18] KVM: arm/arm64: Move HYP IO VAs to the "idmap" range Date: Wed, 6 Dec 2017 14:38:39 +0000 [thread overview] Message-ID: <20171206143839.29223-19-marc.zyngier@arm.com> (raw) In-Reply-To: <20171206143839.29223-1-marc.zyngier@arm.com> We so far mapped our HYP IO (which is essencially the GICv2 control registers) using the same method as for memory. It recently appeared that is a bit unsafe: we compute the HYP VA using the kern_hyp_va helper, but that helper is only designed to deal with kernel VAs coming from the linear map, and not from the vmalloc region... This could in turn cause some bad aliasing between the two, amplified by the new VA randomisation. A solution is to come up with our very own basic VA allocator for MMIO. Since half of the HYP address space only contains a single page (the idmap), we have plenty to borrow from. Let's use the idmap as a base, and allocate downwards from it. GICv2 now lives on the other side of the great VA barrier. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/mmu.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 9f73a8a17147..d843548abd3d 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -43,6 +43,9 @@ static unsigned long hyp_idmap_start; static unsigned long hyp_idmap_end; static phys_addr_t hyp_idmap_vector; +static DEFINE_MUTEX(io_map_lock); +static unsigned long io_map_base; + #define S2_PGD_SIZE (PTRS_PER_S2_PGD * sizeof(pgd_t)) #define hyp_pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t)) @@ -723,7 +726,8 @@ int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size, void __iomem **kaddr, void __iomem **haddr) { - unsigned long start, end; + pgd_t *pgd = hyp_pgd; + unsigned long base; int ret; *kaddr = ioremap(phys_addr, size); @@ -735,19 +739,26 @@ int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size, return 0; } + mutex_lock(&io_map_lock); + + base = io_map_base - size; + base &= ~(size - 1); + + if (__kvm_cpu_uses_extended_idmap()) + pgd = boot_hyp_pgd; - start = kern_hyp_va((unsigned long)*kaddr); - end = kern_hyp_va((unsigned long)*kaddr + size); - ret = __create_hyp_mappings(hyp_pgd, start, end, + ret = __create_hyp_mappings(pgd, base, base + size, __phys_to_pfn(phys_addr), PAGE_HYP_DEVICE); if (ret) { iounmap(*kaddr); *kaddr = NULL; } else { - *haddr = (void __iomem *)start; + *haddr = (void __iomem *)base; + io_map_base = base; } + mutex_unlock(&io_map_lock); return ret; } @@ -1828,6 +1839,7 @@ int kvm_mmu_init(void) goto out; } + io_map_base = hyp_idmap_start; return 0; out: free_hyp_pgds(); -- 2.14.2
next prev parent reply other threads:[~2017-12-06 14:38 UTC|newest] Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-12-06 14:38 [PATCH 00/18] KVM/arm64: Randomise EL2 mappings Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 01/18] arm64: asm-offsets: Avoid clashing DMA definitions Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 02/18] arm64: asm-offsets: Remove unused definitions Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 03/18] arm64: asm-offsets: Remove potential circular dependency Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 04/18] arm64: alternatives: Enforce alignment of struct alt_instr Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:48 ` Konrad Rzeszutek Wilk 2017-12-06 14:48 ` Konrad Rzeszutek Wilk 2017-12-06 14:57 ` Marc Zyngier 2017-12-06 14:57 ` Marc Zyngier 2017-12-06 15:18 ` Konrad Rzeszutek Wilk 2017-12-06 15:18 ` Konrad Rzeszutek Wilk 2017-12-06 15:39 ` Marc Zyngier 2017-12-06 15:39 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 05/18] arm64: alternatives: Add dynamic patching feature Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 06/18] arm64: insn: Add N immediate encoding Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 07/18] arm64: insn: Add encoder for bitwise operations using litterals Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 08/18] arm64: KVM: Dynamically patch the kernel/hyp VA mask Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 09/18] arm64: cpufeatures: Drop the ARM64_HYP_OFFSET_LOW feature flag Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 10/18] arm64; insn: Add encoder for the EXTR instruction Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 11/18] arm64: insn: Allow ADD/SUB (immediate) with LSL #12 Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 12/18] arm64: KVM: Introduce EL2 VA randomisation Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 13/18] arm64: Update the KVM memory map documentation Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 14/18] KVM: arm/arm64: Do not use kern_hyp_va() with kvm_vgic_global_state Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 15/18] KVM: arm/arm64: Demote HYP VA range display to being a debug feature Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 16/18] KVM: arm/arm64: Move ioremap calls to create_hyp_io_mappings Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` [PATCH 17/18] KVM: arm/arm64: Keep GICv2 HYP VAs in kvm_vgic_global_state Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier 2017-12-06 14:38 ` Marc Zyngier [this message] 2017-12-06 14:38 ` [PATCH 18/18] KVM: arm/arm64: Move HYP IO VAs to the "idmap" range Marc Zyngier
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