when passthrough some pcie device, such as gpus(including
Nvidia and AMD),kvm will report:"Unsupported FSC: EC=0x24
xFSC=0x21 ESR_EL2=0x92000061" err.the main reason is vfio
ioremap vga memory type by DEVICE_nGnRnE, and kvm setting
memory type to PAGE_S2_DEVICE(DEVICE_nGnRE), but in guestos,
all of device io memory type when ioremapping (including gpu
driver TTM memory type) is setting to MT_NORMAL_NC.
according to ARM64 stage1&stage2 conbining rules.
memory type attributes combining rules:
Normal-WB<Normal-WT<NormalNC<Device-GRE<Device-nGRE<
DevicenGnRE<Device-nGnRnE
Normal-WB is weakest,Device-nGnRnE is strongest.
refferring to 'Arm Architecture Reference Manual Armv8,
for Armv8-A architecture profile' pdf, chapter B2.8
refferring to 'ARM System Memory Management Unit Architecture
Specification SMMU architecture version 3.0 and version 3.1' pdf,
chapter 13.1.5
therefore, the I/O memory attribute of the VM is setting to
DevicenGnRE maybe is a mistake. it causes all device memory
accessing in the virtual machine must be aligned.
To summarize: stage2 memory type cannot be stronger than stage1
in arm64 archtechture.
Signed-off-by: xieming <xieming@xxxxxxxxxx>
---
arch/arm/include/asm/kvm_mmu.h | 3 ++-
arch/arm64/include/asm/kvm_mmu.h | 3 ++-
arch/arm64/include/asm/memory.h | 4 +++-
arch/arm64/include/asm/pgtable-prot.h | 2 +-
drivers/vfio/pci/vfio_pci.c | 7 +++++++
virt/kvm/arm/mmu.c | 19 ++++++++++++++++---
virt/kvm/arm/vgic/vgic-v2.c | 2 +-
7 files changed, 32 insertions(+), 8 deletions(-)
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 523c499e42db..5c7869d25b62 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -64,7 +64,8 @@ void stage2_unmap_vm(struct kvm *kvm);
int kvm_alloc_stage2_pgd(struct kvm *kvm);
void kvm_free_stage2_pgd(struct kvm *kvm);
int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
- phys_addr_t pa, unsigned long size, bool writable);
+ phys_addr_t pa, unsigned long size,
+ bool writable, bool writecombine);
int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run);
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index b2558447c67d..3f98286c7498 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -158,7 +158,8 @@ void stage2_unmap_vm(struct kvm *kvm);
int kvm_alloc_stage2_pgd(struct kvm *kvm);
void kvm_free_stage2_pgd(struct kvm *kvm);
int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
- phys_addr_t pa, unsigned long size, bool writable);
+ phys_addr_t pa, unsigned long size,
+ bool writable, bool writecombine);
int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run);
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 56562ff01076..22565cc8ec20 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -158,13 +158,15 @@
* Memory types for Stage-2 translation
*/
#define MT_S2_NORMAL 0xf
+#define MT_S2_NORMAL_NC 0x5
#define MT_S2_DEVICE_nGnRE 0x1
/*
* Memory types for Stage-2 translation when ID_AA64MMFR2_EL1.FWB is 0001
- * Stage-2 enforces Normal-WB and Device-nGnRE
+ * Stage-2 enforces Normal-WB and Device-nGnRE and Normal-NC
*/
#define MT_S2_FWB_NORMAL 6
+#define MT_S2_FWB_NORMAL_NC 5
#define MT_S2_FWB_DEVICE_nGnRE 1
#ifdef CONFIG_ARM64_4K_PAGES
diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index af547be1779b..b94e93135fea 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -88,8 +88,8 @@
})
#define PAGE_S2 __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PAGE_S2_XN)
+#define PAGE_S2_NC __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL_NC) | PTE_S2_RDONLY | PAGE_S2_XN)
#define PAGE_S2_DEVICE __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PAGE_S2_XN)
-
#define PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
/* shared+writable pages are clean by default, hence PTE_RDONLY|PTE_WRITE */
#define PAGE_SHARED __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 51b791c750f1..6f66efb71743 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1452,7 +1452,14 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma)
}
vma->vm_private_data = vdev;
+#ifdef CONFIG_ARM64
+ if (vfio_pci_is_vga(pdev))
+ vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+ else
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+#else
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+#endif
vma->vm_pgoff = (pci_resource_start(pdev, index) >> PAGE_SHIFT) + pgoff;
/*
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 11103b75c596..a46a58696834 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -206,6 +206,17 @@ static inline void kvm_pgd_populate(pgd_t *pgdp, pud_t *pudp)
dsb(ishst);
}
+/**
+ * is_vma_write_combine - check if VMA is mapped with writecombine or not
+ * Return true if VMA mapped with MT_NORMAL_NC otherwise fasle
+ */
+static inline bool is_vma_write_combine(struct vm_area_struct *vma)
+{
+ pteval_t pteval = pgprot_val(vma->vm_page_prot);
+
+ return ((pteval & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_NC));
+}
+
/*
* Unmapping vs dcache management:
*
@@ -1198,7 +1209,8 @@ static int stage2_pmdp_test_and_clear_young(pmd_t *pmd)
* @size: The size of the mapping
*/
int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
- phys_addr_t pa, unsigned long size, bool writable)
+ phys_addr_t pa, unsigned long size,
+ bool writable, bool writecombine)
{
phys_addr_t addr, end;
int ret = 0;
@@ -1209,7 +1221,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
pfn = __phys_to_pfn(pa);
for (addr = guest_ipa; addr < end; addr += PAGE_SIZE) {
- pte_t pte = pfn_pte(pfn, PAGE_S2_DEVICE);
+ pte_t pte = pfn_pte(pfn, writecombine ? PAGE_S2_NC : PAGE_S2_DEVICE);
if (writable)
pte = kvm_s2pte_mkwrite(pte);
@@ -2135,7 +2147,8 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
ret = kvm_phys_addr_ioremap(kvm, gpa, pa,
vm_end - vm_start,
- writable);
+ writable,
+ is_vma_write_combine(vma));
if (ret)
break;
}
diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index 91b14dfacd1d..bc9f5a9a1fd9 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -352,7 +352,7 @@ int vgic_v2_map_resources(struct kvm *kvm)
if (!static_branch_unlikely(&vgic_v2_cpuif_trap)) {
ret = kvm_phys_addr_ioremap(kvm, dist->vgic_cpu_base,
kvm_vgic_global_state.vcpu_base,
- KVM_VGIC_V2_CPU_SIZE, true);
+ KVM_VGIC_V2_CPU_SIZE, true, false);
if (ret) {
kvm_err("Unable to remap VGIC CPU to VCPU\n");
goto out;
--
2.27.0
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