On Tue, 12 Oct 2021 14:25:10 +0100
Alexandru Elisei <alexandru.elisei@xxxxxxx> wrote:
> When allocating MMIO space for the MSI-X table, kvmtool rounds the
> allocation to the host's page size to make it as easy as possible for the
> guest to map the table to a page, if it wants to (and doesn't do BAR
> reassignment, like the x86 architecture for example). However, the host's
> page size can differ from the guest's on architectures which support
> multiple page sizes. For example, arm64 supports three different page size,
> and it is possible for the host to be using 4k pages, while the guest is
> using 64k pages.
>
> To make sure the allocation is always aligned to a guest's page size, round
> it up to the maximum architectural page size. Do the same for the pending
> bit array if it lives in its own BAR.
>
> Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Thanks for adding MAX_PAGE_SIZE, looks alright now.
Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>
Cheers,
Andre
> ---
> arm/aarch32/include/kvm/kvm-arch.h | 4 ++++
> arm/aarch64/include/kvm/kvm-arch.h | 4 ++++
> mips/include/kvm/kvm-arch.h | 3 +++
> powerpc/include/kvm/kvm-arch.h | 3 +++
> vfio/pci.c | 6 ++++--
> x86/include/kvm/kvm-arch.h | 3 +++
> 6 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/arm/aarch32/include/kvm/kvm-arch.h b/arm/aarch32/include/kvm/kvm-arch.h
> index a772bb1..bee2fc2 100644
> --- a/arm/aarch32/include/kvm/kvm-arch.h
> +++ b/arm/aarch32/include/kvm/kvm-arch.h
> @@ -1,10 +1,14 @@
> #ifndef KVM__KVM_ARCH_H
> #define KVM__KVM_ARCH_H
>
> +#include <linux/sizes.h>
> +
> #define kvm__arch_get_kern_offset(...) 0x8000
>
> #define ARM_MAX_MEMORY(...) ARM_LOMAP_MAX_MEMORY
>
> +#define MAX_PAGE_SIZE SZ_4K
> +
> #include "arm-common/kvm-arch.h"
>
> #endif /* KVM__KVM_ARCH_H */
> diff --git a/arm/aarch64/include/kvm/kvm-arch.h b/arm/aarch64/include/kvm/kvm-arch.h
> index 159567b..5e5ee41 100644
> --- a/arm/aarch64/include/kvm/kvm-arch.h
> +++ b/arm/aarch64/include/kvm/kvm-arch.h
> @@ -1,6 +1,8 @@
> #ifndef KVM__KVM_ARCH_H
> #define KVM__KVM_ARCH_H
>
> +#include <linux/sizes.h>
> +
> struct kvm;
> unsigned long long kvm__arch_get_kern_offset(struct kvm *kvm, int fd);
> int kvm__arch_get_ipa_limit(struct kvm *kvm);
> @@ -21,6 +23,8 @@ int kvm__arch_get_ipa_limit(struct kvm *kvm);
> max_ram; \
> })
>
> +#define MAX_PAGE_SIZE SZ_64K
> +
> #include "arm-common/kvm-arch.h"
>
> #endif /* KVM__KVM_ARCH_H */
> diff --git a/mips/include/kvm/kvm-arch.h b/mips/include/kvm/kvm-arch.h
> index fdc09d8..e2f048a 100644
> --- a/mips/include/kvm/kvm-arch.h
> +++ b/mips/include/kvm/kvm-arch.h
> @@ -1,6 +1,7 @@
> #ifndef KVM__KVM_ARCH_H
> #define KVM__KVM_ARCH_H
>
> +#include <linux/sizes.h>
>
> /*
> * Guest memory map is:
> @@ -36,6 +37,8 @@
>
> #define VIRTIO_DEFAULT_TRANS(kvm) VIRTIO_PCI
>
> +#define MAX_PAGE_SIZE SZ_64K
> +
> #include <stdbool.h>
>
> #include "linux/types.h"
> diff --git a/powerpc/include/kvm/kvm-arch.h b/powerpc/include/kvm/kvm-arch.h
> index 26d440b..8eeca50 100644
> --- a/powerpc/include/kvm/kvm-arch.h
> +++ b/powerpc/include/kvm/kvm-arch.h
> @@ -13,6 +13,7 @@
>
> #include <stdbool.h>
> #include <linux/types.h>
> +#include <linux/sizes.h>
> #include <time.h>
>
> /*
> @@ -48,6 +49,8 @@
>
> #define KVM_IOEVENTFD_HAS_PIO 0
>
> +#define MAX_PAGE_SIZE SZ_256K
> +
> #define VIRTIO_DEFAULT_TRANS(kvm) VIRTIO_PCI
>
> struct spapr_phb;
> diff --git a/vfio/pci.c b/vfio/pci.c
> index a08352d..78f5ca5 100644
> --- a/vfio/pci.c
> +++ b/vfio/pci.c
> @@ -1,3 +1,5 @@
> +#include "linux/sizes.h"
> +
> #include "kvm/irq.h"
> #include "kvm/kvm.h"
> #include "kvm/kvm-cpu.h"
> @@ -926,7 +928,7 @@ static int vfio_pci_create_msix_table(struct kvm *kvm, struct vfio_device *vdev)
> if (!info.size)
> return -EINVAL;
>
> - map_size = ALIGN(info.size, PAGE_SIZE);
> + map_size = ALIGN(info.size, MAX_PAGE_SIZE);
> table->guest_phys_addr = pci_get_mmio_block(map_size);
> if (!table->guest_phys_addr) {
> pr_err("cannot allocate MMIO space");
> @@ -958,7 +960,7 @@ static int vfio_pci_create_msix_table(struct kvm *kvm, struct vfio_device *vdev)
> if (!info.size)
> return -EINVAL;
>
> - map_size = ALIGN(info.size, PAGE_SIZE);
> + map_size = ALIGN(info.size, MAX_PAGE_SIZE);
> pba->guest_phys_addr = pci_get_mmio_block(map_size);
> if (!pba->guest_phys_addr) {
> pr_err("cannot allocate MMIO space");
> diff --git a/x86/include/kvm/kvm-arch.h b/x86/include/kvm/kvm-arch.h
> index 85cd336..d8a7312 100644
> --- a/x86/include/kvm/kvm-arch.h
> +++ b/x86/include/kvm/kvm-arch.h
> @@ -5,6 +5,7 @@
>
> #include <stdbool.h>
> #include <linux/types.h>
> +#include <linux/sizes.h>
> #include <time.h>
>
> /*
> @@ -30,6 +31,8 @@
>
> #define KVM_IOEVENTFD_HAS_PIO 1
>
> +#define MAX_PAGE_SIZE SZ_4K
> +
> #define VIRTIO_DEFAULT_TRANS(kvm) VIRTIO_PCI
>
> struct kvm_arch {
