lkml.org 
[lkml]   [2023]   [Oct]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH v6 02/25] x86/fpu/xstate: Fix guest fpstate allocation size calculation
    From
    On Thu, Sep 14, 2023, Yang Weijiang wrote:
    > Fix guest xsave area allocation size from fpu_user_cfg.default_size to
    > fpu_kernel_cfg.default_size so that the xsave area size is consistent
    > with fpstate->size set in __fpstate_reset().
    >
    > With the fix, guest fpstate size is sufficient for KVM supported guest
    > xfeatures.
    >
    > Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
    > ---
    > arch/x86/kernel/fpu/core.c | 4 +++-
    > 1 file changed, 3 insertions(+), 1 deletion(-)
    >
    > diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
    > index a86d37052a64..a42d8ad26ce6 100644
    > --- a/arch/x86/kernel/fpu/core.c
    > +++ b/arch/x86/kernel/fpu/core.c
    > @@ -220,7 +220,9 @@ bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu)
    > struct fpstate *fpstate;
    > unsigned int size;
    >
    > - size = fpu_user_cfg.default_size + ALIGN(offsetof(struct fpstate, regs), 64);
    > + size = fpu_kernel_cfg.default_size +
    > + ALIGN(offsetof(struct fpstate, regs), 64);

    Shouldn't all the other calculations in this function also switch to fpu_kernel_cfg?
    At the very least, this looks wrong when paired with the above:

    gfpu->uabi_size = sizeof(struct kvm_xsave);
    if (WARN_ON_ONCE(fpu_user_cfg.default_size > gfpu->uabi_size))
    gfpu->uabi_size = fpu_user_cfg.default_size;

    \
     
     \ /
      Last update: 2023-10-21 02:40    [W:6.553 / U:0.036 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site