[prev in list] [next in list] [prev in thread] [next in thread]
List: linux-api
Subject: Re: [PATCH v5 07/13] KVM: Add KVM_EXIT_MEMORY_ERROR exit
From: Sean Christopherson <seanjc () google ! com>
Date: 2022-03-28 22:33:37
Message-ID: YkI3wa3rmWTOrpmw () google ! com
[Download RAW message or body]
On Thu, Mar 10, 2022, Chao Peng wrote:
> This new KVM exit allows userspace to handle memory-related errors. It
> indicates an error happens in KVM at guest memory range [gpa, gpa+size).
> The flags includes additional information for userspace to handle the
> error. Currently bit 0 is defined as 'private memory' where '1'
> indicates error happens due to private memory access and '0' indicates
> error happens due to shared memory access.
>
> After private memory is enabled, this new exit will be used for KVM to
> exit to userspace for shared memory <-> private memory conversion in
> memory encryption usage.
>
> In such usage, typically there are two kind of memory conversions:
> - explicit conversion: happens when guest explicitly calls into KVM to
> map a range (as private or shared), KVM then exits to userspace to
> do the map/unmap operations.
> - implicit conversion: happens in KVM page fault handler.
> * if the fault is due to a private memory access then causes a
> userspace exit for a shared->private conversion request when the
> page has not been allocated in the private memory backend.
> * If the fault is due to a shared memory access then causes a
> userspace exit for a private->shared conversion request when the
> page has already been allocated in the private memory backend.
>
> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
> Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
> ---
> Documentation/virt/kvm/api.rst | 22 ++++++++++++++++++++++
> include/uapi/linux/kvm.h | 9 +++++++++
> 2 files changed, 31 insertions(+)
>
> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> index f76ac598606c..bad550c2212b 100644
> --- a/Documentation/virt/kvm/api.rst
> +++ b/Documentation/virt/kvm/api.rst
> @@ -6216,6 +6216,28 @@ array field represents return values. The userspace should update the return
> values of SBI call before resuming the VCPU. For more details on RISC-V SBI
> spec refer, https://github.com/riscv/riscv-sbi-doc.
>
> +::
> +
> + /* KVM_EXIT_MEMORY_ERROR */
> + struct {
> + #define KVM_MEMORY_EXIT_FLAG_PRIVATE (1 << 0)
> + __u32 flags;
> + __u32 padding;
> + __u64 gpa;
> + __u64 size;
> + } memory;
> +If exit reason is KVM_EXIT_MEMORY_ERROR then it indicates that the VCPU has
Doh, I'm pretty sure I suggested KVM_EXIT_MEMORY_ERROR. Any objection to using
KVM_EXIT_MEMORY_FAULT instead of KVM_EXIT_MEMORY_ERROR? "ERROR" makes me think
of ECC errors, i.e. uncorrected #MC in x86 land, not more generic "faults". That
would align nicely with -EFAULT.
> +encountered a memory error which is not handled by KVM kernel module and
> +userspace may choose to handle it. The 'flags' field indicates the memory
> +properties of the exit.
[prev in list] [next in list] [prev in thread] [next in thread]
Configure |
About |
News |
Add a list |
Sponsored by KoreLogic