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Message-ID: <20190731144332.yjrrwbqvl7lmudiz@kamzik.brq.redhat.com>
Date: Wed, 31 Jul 2019 16:43:32 +0200
From: Andrew Jones <drjones@...hat.com>
To: Thomas Huth <thuth@...hat.com>
Cc: kvm@...r.kernel.org,
Christian Borntraeger <borntraeger@...ibm.com>,
Janosch Frank <frankja@...ux.ibm.com>,
linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-s390@...r.kernel.org, David Hildenbrand <david@...hat.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Peter Xu <peterx@...hat.com>
Subject: Re: [PATCH v2 1/3] KVM: selftests: Split ucall.c into architecture
specific files
On Wed, Jul 31, 2019 at 03:32:14PM +0200, Thomas Huth wrote:
> The way we exit from a guest to userspace is very specific to the
> architecture: On x86, we use PIO, on aarch64 we are using MMIO and on
> s390x we're going to use an instruction instead. The possibility to
> select a type via the ucall_type_t enum is currently also completely
> unused, so the code in ucall.c currently looks more complex than
> required. Let's split this up into architecture specific ucall.c
> files instead, so we can get rid of the #ifdefs and the unnecessary
> ucall_type_t handling.
>
> Signed-off-by: Thomas Huth <thuth@...hat.com>
> ---
> tools/testing/selftests/kvm/Makefile | 6 +-
> tools/testing/selftests/kvm/dirty_log_test.c | 2 +-
> .../testing/selftests/kvm/include/kvm_util.h | 8 +-
> .../testing/selftests/kvm/lib/aarch64/ucall.c | 112 +++++++++++++
> tools/testing/selftests/kvm/lib/ucall.c | 157 ------------------
> .../testing/selftests/kvm/lib/x86_64/ucall.c | 56 +++++++
> 6 files changed, 173 insertions(+), 168 deletions(-)
> create mode 100644 tools/testing/selftests/kvm/lib/aarch64/ucall.c
> delete mode 100644 tools/testing/selftests/kvm/lib/ucall.c
> create mode 100644 tools/testing/selftests/kvm/lib/x86_64/ucall.c
>
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index ba7849751989..a51e3b83df40 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -7,9 +7,9 @@ top_srcdir = ../../../..
> KSFT_KHDR_INSTALL := 1
> UNAME_M := $(shell uname -m)
>
> -LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/ucall.c lib/sparsebit.c
> -LIBKVM_x86_64 = lib/x86_64/processor.c lib/x86_64/vmx.c
> -LIBKVM_aarch64 = lib/aarch64/processor.c
> +LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/sparsebit.c
> +LIBKVM_x86_64 = lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/ucall.c
> +LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c
> LIBKVM_s390x = lib/s390x/processor.c
>
> TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test
> diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
> index ceb52b952637..5d5ae1be4984 100644
> --- a/tools/testing/selftests/kvm/dirty_log_test.c
> +++ b/tools/testing/selftests/kvm/dirty_log_test.c
> @@ -337,7 +337,7 @@ static void run_test(enum vm_guest_mode mode, unsigned long iterations,
> vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
> #endif
> #ifdef __aarch64__
> - ucall_init(vm, UCALL_MMIO, NULL);
> + ucall_init(vm, NULL);
> #endif
>
> /* Export the shared variables to the guest */
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index e0e66b115ef2..5463b7896a0a 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -165,12 +165,6 @@ int vm_create_device(struct kvm_vm *vm, struct kvm_create_device *cd);
> memcpy(&(g), _p, sizeof(g)); \
> })
>
> -/* ucall implementation types */
> -typedef enum {
> - UCALL_PIO,
> - UCALL_MMIO,
> -} ucall_type_t;
> -
> /* Common ucalls */
> enum {
> UCALL_NONE,
> @@ -186,7 +180,7 @@ struct ucall {
> uint64_t args[UCALL_MAX_ARGS];
> };
>
> -void ucall_init(struct kvm_vm *vm, ucall_type_t type, void *arg);
> +void ucall_init(struct kvm_vm *vm, void *arg);
> void ucall_uninit(struct kvm_vm *vm);
> void ucall(uint64_t cmd, int nargs, ...);
> uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc);
> diff --git a/tools/testing/selftests/kvm/lib/aarch64/ucall.c b/tools/testing/selftests/kvm/lib/aarch64/ucall.c
> new file mode 100644
> index 000000000000..f69f951a48c0
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/aarch64/ucall.c
> @@ -0,0 +1,112 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ucall support. A ucall is a "hypercall to userspace".
> + *
> + * Copyright (C) 2018, Red Hat, Inc.
> + */
> +#include "kvm_util.h"
> +#include "kvm_util_internal.h"
This needs to be #include "../kvm_util_internal.h"
otherwise we get
lib/aarch64/ucall.c:8:10: fatal error: kvm_util_internal.h: No such file or directory
#include "kvm_util_internal.h"
With that change compilation completes and the tests run.
Thanks,
drew
> +
> +static vm_vaddr_t *ucall_exit_mmio_addr;
> +
> +static bool ucall_mmio_init(struct kvm_vm *vm, vm_paddr_t gpa)
> +{
> + if (kvm_userspace_memory_region_find(vm, gpa, gpa + 1))
> + return false;
> +
> + virt_pg_map(vm, gpa, gpa, 0);
> +
> + ucall_exit_mmio_addr = (vm_vaddr_t *)gpa;
> + sync_global_to_guest(vm, ucall_exit_mmio_addr);
> +
> + return true;
> +}
> +
> +void ucall_init(struct kvm_vm *vm, void *arg)
> +{
> + vm_paddr_t gpa, start, end, step, offset;
> + unsigned int bits;
> + bool ret;
> +
> + if (arg) {
> + gpa = (vm_paddr_t)arg;
> + ret = ucall_mmio_init(vm, gpa);
> + TEST_ASSERT(ret, "Can't set ucall mmio address to %lx", gpa);
> + return;
> + }
> +
> + /*
> + * Find an address within the allowed physical and virtual address
> + * spaces, that does _not_ have a KVM memory region associated with
> + * it. Identity mapping an address like this allows the guest to
> + * access it, but as KVM doesn't know what to do with it, it
> + * will assume it's something userspace handles and exit with
> + * KVM_EXIT_MMIO. Well, at least that's how it works for AArch64.
> + * Here we start with a guess that the addresses around 5/8th
> + * of the allowed space are unmapped and then work both down and
> + * up from there in 1/16th allowed space sized steps.
> + *
> + * Note, we need to use VA-bits - 1 when calculating the allowed
> + * virtual address space for an identity mapping because the upper
> + * half of the virtual address space is the two's complement of the
> + * lower and won't match physical addresses.
> + */
> + bits = vm->va_bits - 1;
> + bits = vm->pa_bits < bits ? vm->pa_bits : bits;
> + end = 1ul << bits;
> + start = end * 5 / 8;
> + step = end / 16;
> + for (offset = 0; offset < end - start; offset += step) {
> + if (ucall_mmio_init(vm, start - offset))
> + return;
> + if (ucall_mmio_init(vm, start + offset))
> + return;
> + }
> + TEST_ASSERT(false, "Can't find a ucall mmio address");
> +}
> +
> +void ucall_uninit(struct kvm_vm *vm)
> +{
> + ucall_exit_mmio_addr = 0;
> + sync_global_to_guest(vm, ucall_exit_mmio_addr);
> +}
> +
> +void ucall(uint64_t cmd, int nargs, ...)
> +{
> + struct ucall uc = {
> + .cmd = cmd,
> + };
> + va_list va;
> + int i;
> +
> + nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS;
> +
> + va_start(va, nargs);
> + for (i = 0; i < nargs; ++i)
> + uc.args[i] = va_arg(va, uint64_t);
> + va_end(va);
> +
> + *ucall_exit_mmio_addr = (vm_vaddr_t)&uc;
> +}
> +
> +uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
> +{
> + struct kvm_run *run = vcpu_state(vm, vcpu_id);
> + struct ucall ucall = {};
> +
> + if (run->exit_reason == KVM_EXIT_MMIO &&
> + run->mmio.phys_addr == (uint64_t)ucall_exit_mmio_addr) {
> + vm_vaddr_t gva;
> +
> + TEST_ASSERT(run->mmio.is_write && run->mmio.len == 8,
> + "Unexpected ucall exit mmio address access");
> + memcpy(&gva, run->mmio.data, sizeof(gva));
> + memcpy(&ucall, addr_gva2hva(vm, gva), sizeof(ucall));
> +
> + vcpu_run_complete_io(vm, vcpu_id);
> + if (uc)
> + memcpy(uc, &ucall, sizeof(ucall));
> + }
> +
> + return ucall.cmd;
> +}
> diff --git a/tools/testing/selftests/kvm/lib/ucall.c b/tools/testing/selftests/kvm/lib/ucall.c
> deleted file mode 100644
> index dd9a66700f96..000000000000
> --- a/tools/testing/selftests/kvm/lib/ucall.c
> +++ /dev/null
> @@ -1,157 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * ucall support. A ucall is a "hypercall to userspace".
> - *
> - * Copyright (C) 2018, Red Hat, Inc.
> - */
> -#include "kvm_util.h"
> -#include "kvm_util_internal.h"
> -
> -#define UCALL_PIO_PORT ((uint16_t)0x1000)
> -
> -static ucall_type_t ucall_type;
> -static vm_vaddr_t *ucall_exit_mmio_addr;
> -
> -static bool ucall_mmio_init(struct kvm_vm *vm, vm_paddr_t gpa)
> -{
> - if (kvm_userspace_memory_region_find(vm, gpa, gpa + 1))
> - return false;
> -
> - virt_pg_map(vm, gpa, gpa, 0);
> -
> - ucall_exit_mmio_addr = (vm_vaddr_t *)gpa;
> - sync_global_to_guest(vm, ucall_exit_mmio_addr);
> -
> - return true;
> -}
> -
> -void ucall_init(struct kvm_vm *vm, ucall_type_t type, void *arg)
> -{
> - ucall_type = type;
> - sync_global_to_guest(vm, ucall_type);
> -
> - if (type == UCALL_PIO)
> - return;
> -
> - if (type == UCALL_MMIO) {
> - vm_paddr_t gpa, start, end, step, offset;
> - unsigned bits;
> - bool ret;
> -
> - if (arg) {
> - gpa = (vm_paddr_t)arg;
> - ret = ucall_mmio_init(vm, gpa);
> - TEST_ASSERT(ret, "Can't set ucall mmio address to %lx", gpa);
> - return;
> - }
> -
> - /*
> - * Find an address within the allowed physical and virtual address
> - * spaces, that does _not_ have a KVM memory region associated with
> - * it. Identity mapping an address like this allows the guest to
> - * access it, but as KVM doesn't know what to do with it, it
> - * will assume it's something userspace handles and exit with
> - * KVM_EXIT_MMIO. Well, at least that's how it works for AArch64.
> - * Here we start with a guess that the addresses around 5/8th
> - * of the allowed space are unmapped and then work both down and
> - * up from there in 1/16th allowed space sized steps.
> - *
> - * Note, we need to use VA-bits - 1 when calculating the allowed
> - * virtual address space for an identity mapping because the upper
> - * half of the virtual address space is the two's complement of the
> - * lower and won't match physical addresses.
> - */
> - bits = vm->va_bits - 1;
> - bits = vm->pa_bits < bits ? vm->pa_bits : bits;
> - end = 1ul << bits;
> - start = end * 5 / 8;
> - step = end / 16;
> - for (offset = 0; offset < end - start; offset += step) {
> - if (ucall_mmio_init(vm, start - offset))
> - return;
> - if (ucall_mmio_init(vm, start + offset))
> - return;
> - }
> - TEST_ASSERT(false, "Can't find a ucall mmio address");
> - }
> -}
> -
> -void ucall_uninit(struct kvm_vm *vm)
> -{
> - ucall_type = 0;
> - sync_global_to_guest(vm, ucall_type);
> - ucall_exit_mmio_addr = 0;
> - sync_global_to_guest(vm, ucall_exit_mmio_addr);
> -}
> -
> -static void ucall_pio_exit(struct ucall *uc)
> -{
> -#ifdef __x86_64__
> - asm volatile("in %[port], %%al"
> - : : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax");
> -#endif
> -}
> -
> -static void ucall_mmio_exit(struct ucall *uc)
> -{
> - *ucall_exit_mmio_addr = (vm_vaddr_t)uc;
> -}
> -
> -void ucall(uint64_t cmd, int nargs, ...)
> -{
> - struct ucall uc = {
> - .cmd = cmd,
> - };
> - va_list va;
> - int i;
> -
> - nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS;
> -
> - va_start(va, nargs);
> - for (i = 0; i < nargs; ++i)
> - uc.args[i] = va_arg(va, uint64_t);
> - va_end(va);
> -
> - switch (ucall_type) {
> - case UCALL_PIO:
> - ucall_pio_exit(&uc);
> - break;
> - case UCALL_MMIO:
> - ucall_mmio_exit(&uc);
> - break;
> - };
> -}
> -
> -uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
> -{
> - struct kvm_run *run = vcpu_state(vm, vcpu_id);
> - struct ucall ucall = {};
> - bool got_ucall = false;
> -
> -#ifdef __x86_64__
> - if (ucall_type == UCALL_PIO && run->exit_reason == KVM_EXIT_IO &&
> - run->io.port == UCALL_PIO_PORT) {
> - struct kvm_regs regs;
> - vcpu_regs_get(vm, vcpu_id, ®s);
> - memcpy(&ucall, addr_gva2hva(vm, (vm_vaddr_t)regs.rdi), sizeof(ucall));
> - got_ucall = true;
> - }
> -#endif
> - if (ucall_type == UCALL_MMIO && run->exit_reason == KVM_EXIT_MMIO &&
> - run->mmio.phys_addr == (uint64_t)ucall_exit_mmio_addr) {
> - vm_vaddr_t gva;
> - TEST_ASSERT(run->mmio.is_write && run->mmio.len == 8,
> - "Unexpected ucall exit mmio address access");
> - memcpy(&gva, run->mmio.data, sizeof(gva));
> - memcpy(&ucall, addr_gva2hva(vm, gva), sizeof(ucall));
> - got_ucall = true;
> - }
> -
> - if (got_ucall) {
> - vcpu_run_complete_io(vm, vcpu_id);
> - if (uc)
> - memcpy(uc, &ucall, sizeof(ucall));
> - }
> -
> - return ucall.cmd;
> -}
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/ucall.c b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
> new file mode 100644
> index 000000000000..4bfc9a90b1de
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
> @@ -0,0 +1,56 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ucall support. A ucall is a "hypercall to userspace".
> + *
> + * Copyright (C) 2018, Red Hat, Inc.
> + */
> +#include "kvm_util.h"
> +
> +#define UCALL_PIO_PORT ((uint16_t)0x1000)
> +
> +void ucall_init(struct kvm_vm *vm, void *arg)
> +{
> +}
> +
> +void ucall_uninit(struct kvm_vm *vm)
> +{
> +}
> +
> +void ucall(uint64_t cmd, int nargs, ...)
> +{
> + struct ucall uc = {
> + .cmd = cmd,
> + };
> + va_list va;
> + int i;
> +
> + nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS;
> +
> + va_start(va, nargs);
> + for (i = 0; i < nargs; ++i)
> + uc.args[i] = va_arg(va, uint64_t);
> + va_end(va);
> +
> + asm volatile("in %[port], %%al"
> + : : [port] "d" (UCALL_PIO_PORT), "D" (&uc) : "rax");
> +}
> +
> +uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
> +{
> + struct kvm_run *run = vcpu_state(vm, vcpu_id);
> + struct ucall ucall = {};
> +
> + if (run->exit_reason == KVM_EXIT_IO && run->io.port == UCALL_PIO_PORT) {
> + struct kvm_regs regs;
> +
> + vcpu_regs_get(vm, vcpu_id, ®s);
> + memcpy(&ucall, addr_gva2hva(vm, (vm_vaddr_t)regs.rdi),
> + sizeof(ucall));
> +
> + vcpu_run_complete_io(vm, vcpu_id);
> + if (uc)
> + memcpy(uc, &ucall, sizeof(ucall));
> + }
> +
> + return ucall.cmd;
> +}
> --
> 2.21.0
>
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