From 8c3ce496bd612bd21679e445f75fcabb6be997b2 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Sat, 9 Apr 2022 09:15:33 +0530 Subject: [PATCH 1/4] RISC-V: KVM: Don't clear hgatp CSR in kvm_arch_vcpu_put() We might have RISC-V systems (such as QEMU) where VMID is not part of the TLB entry tag so these systems will have to flush all TLB entries upon any change in hgatp.VMID. Currently, we zero-out hgatp CSR in kvm_arch_vcpu_put() and we re-program hgatp CSR in kvm_arch_vcpu_load(). For above described systems, this will flush all TLB entries whenever VCPU exits to user-space hence reducing performance. This patch fixes above described performance issue by not clearing hgatp CSR in kvm_arch_vcpu_put(). Fixes: 34bde9d8b9e6 ("RISC-V: KVM: Implement VCPU world-switch") Cc: stable@vger.kernel.org Signed-off-by: Anup Patel Signed-off-by: Anup Patel --- arch/riscv/kvm/vcpu.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 624166004e36..6785aef4cbd4 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -653,8 +653,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) vcpu->arch.isa); kvm_riscv_vcpu_host_fp_restore(&vcpu->arch.host_context); - csr_write(CSR_HGATP, 0); - csr->vsstatus = csr_read(CSR_VSSTATUS); csr->vsie = csr_read(CSR_VSIE); csr->vstvec = csr_read(CSR_VSTVEC); From fac3725364397f9a40a101f089b86ea655a58d06 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Sat, 9 Apr 2022 09:15:44 +0530 Subject: [PATCH 2/4] KVM: selftests: riscv: Set PTE A and D bits in VS-stage page table Supporting hardware updates of PTE A and D bits is optional for any RISC-V implementation so current software strategy is to always set these bits in both G-stage (hypervisor) and VS-stage (guest kernel). If PTE A and D bits are not set by software (hypervisor or guest) then RISC-V implementations not supporting hardware updates of these bits will cause traps even for perfectly valid PTEs. Based on above explanation, the VS-stage page table created by various KVM selftest applications is not correct because PTE A and D bits are not set. This patch fixes VS-stage page table programming of PTE A and D bits for KVM selftests. Fixes: 3e06cdf10520 ("KVM: selftests: Add initial support for RISC-V 64-bit") Signed-off-by: Anup Patel Tested-by: Mayuresh Chitale Signed-off-by: Anup Patel --- tools/testing/selftests/kvm/include/riscv/processor.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/include/riscv/processor.h b/tools/testing/selftests/kvm/include/riscv/processor.h index dc284c6bdbc3..eca5c622efd2 100644 --- a/tools/testing/selftests/kvm/include/riscv/processor.h +++ b/tools/testing/selftests/kvm/include/riscv/processor.h @@ -101,7 +101,9 @@ static inline void set_reg(struct kvm_vm *vm, uint32_t vcpuid, uint64_t id, #define PGTBL_PTE_WRITE_SHIFT 2 #define PGTBL_PTE_READ_MASK 0x0000000000000002ULL #define PGTBL_PTE_READ_SHIFT 1 -#define PGTBL_PTE_PERM_MASK (PGTBL_PTE_EXECUTE_MASK | \ +#define PGTBL_PTE_PERM_MASK (PGTBL_PTE_ACCESSED_MASK | \ + PGTBL_PTE_DIRTY_MASK | \ + PGTBL_PTE_EXECUTE_MASK | \ PGTBL_PTE_WRITE_MASK | \ PGTBL_PTE_READ_MASK) #define PGTBL_PTE_VALID_MASK 0x0000000000000001ULL From ebdef0de2dbc40e697adaa6b3408130f7a7b8351 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Sat, 9 Apr 2022 09:15:51 +0530 Subject: [PATCH 3/4] KVM: selftests: riscv: Fix alignment of the guest_hang() function The guest_hang() function is used as the default exception handler for various KVM selftests applications by setting it's address in the vstvec CSR. The vstvec CSR requires exception handler base address to be at least 4-byte aligned so this patch fixes alignment of the guest_hang() function. Fixes: 3e06cdf10520 ("KVM: selftests: Add initial support for RISC-V 64-bit") Signed-off-by: Anup Patel Tested-by: Mayuresh Chitale Signed-off-by: Anup Patel --- tools/testing/selftests/kvm/lib/riscv/processor.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/lib/riscv/processor.c b/tools/testing/selftests/kvm/lib/riscv/processor.c index d377f2603d98..3961487a4870 100644 --- a/tools/testing/selftests/kvm/lib/riscv/processor.c +++ b/tools/testing/selftests/kvm/lib/riscv/processor.c @@ -268,7 +268,7 @@ void vcpu_dump(FILE *stream, struct kvm_vm *vm, uint32_t vcpuid, uint8_t indent) core.regs.t3, core.regs.t4, core.regs.t5, core.regs.t6); } -static void guest_hang(void) +static void __aligned(16) guest_hang(void) { while (1) ; From 4054eee9290248bf66c5eacb58879c9aaad37f71 Mon Sep 17 00:00:00 2001 From: Heiko Stuebner Date: Sat, 9 Apr 2022 09:16:00 +0530 Subject: [PATCH 4/4] RISC-V: KVM: include missing hwcap.h into vcpu_fp MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit vcpu_fp uses the riscv_isa_extension mechanism which gets defined in hwcap.h but doesn't include that head file. While it seems to work in most cases, in certain conditions this can lead to build failures like ../arch/riscv/kvm/vcpu_fp.c: In function ‘kvm_riscv_vcpu_fp_reset’: ../arch/riscv/kvm/vcpu_fp.c:22:13: error: implicit declaration of function ‘riscv_isa_extension_available’ [-Werror=implicit-function-declaration] 22 | if (riscv_isa_extension_available(&isa, f) || | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../arch/riscv/kvm/vcpu_fp.c:22:49: error: ‘f’ undeclared (first use in this function) 22 | if (riscv_isa_extension_available(&isa, f) || Fix this by simply including the necessary header. Fixes: 0a86512dc113 ("RISC-V: KVM: Factor-out FP virtualization into separate sources") Signed-off-by: Heiko Stuebner Signed-off-by: Anup Patel --- arch/riscv/kvm/vcpu_fp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/riscv/kvm/vcpu_fp.c b/arch/riscv/kvm/vcpu_fp.c index 4449a976e5a6..d4308c512007 100644 --- a/arch/riscv/kvm/vcpu_fp.c +++ b/arch/riscv/kvm/vcpu_fp.c @@ -11,6 +11,7 @@ #include #include #include +#include #ifdef CONFIG_FPU void kvm_riscv_vcpu_fp_reset(struct kvm_vcpu *vcpu)