[PATCH] RISC-V: KVM: Using user-mode pte within kvm_riscv_gstage_ioremap

[fangyu.yu at linux.alibaba.com]

From: Fangyu Yu <fangyu.yu at linux.alibaba.com>

Currently we use kvm_riscv_gstage_ioremap to map IMSIC gpa to the spa of
guest interrupt file within IMSIC.

The PAGE_KERNEL_IO property does not include user mode settings, so when
accessing the IMSIC address in the virtual machine,  a  guest page fault
will occur, this is not expected.

According to the RISC-V Privileged Architecture Spec, for G-stage address
translation, all memory accesses are considered to be user-level accesses
as though executed in Umode.

Signed-off-by: Fangyu Yu <fangyu.yu at linux.alibaba.com>
---
 arch/riscv/kvm/mmu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 1087ea74567b..800064e96ef6 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -351,6 +351,7 @@ int kvm_riscv_gstage_ioremap(struct kvm *kvm, gpa_t gpa,
 	int ret = 0;
 	unsigned long pfn;
 	phys_addr_t addr, end;
+	pgprot_t prot;
 	struct kvm_mmu_memory_cache pcache = {
 		.gfp_custom = (in_atomic) ? GFP_ATOMIC | __GFP_ACCOUNT : 0,
 		.gfp_zero = __GFP_ZERO,
@@ -359,8 +360,11 @@ int kvm_riscv_gstage_ioremap(struct kvm *kvm, gpa_t gpa,
 	end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK;
 	pfn = __phys_to_pfn(hpa);
 
+	prot = pgprot_noncached(PAGE_WRITE);
+
 	for (addr = gpa; addr < end; addr += PAGE_SIZE) {
-		pte = pfn_pte(pfn, PAGE_KERNEL_IO);
+		pte = pfn_pte(pfn, prot);
+		pte = pte_mkdirty(pte);
 
 		if (!writable)
 			pte = pte_wrprotect(pte);
-- 
2.39.3 (Apple Git-146)