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Message-ID: <CALzav=eWVPs9r-P2kUiKD=BUHj5AKC912ia+++0204EXwEB6=Q@mail.gmail.com>
Date: Mon, 8 Jun 2015 17:36:16 -0700
From: David Matlack <dmatlack@...gle.com>
To: Xiao Guangrong <guangrong.xiao@...ux.intel.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>,
Gleb Natapov <gleb@...nel.org>,
Marcelo Tosatti <mtosatti@...hat.com>,
kvm list <kvm@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 12/15] KVM: MTRR: introduce mtrr_for_each_mem_type
On Sat, May 30, 2015 at 3:59 AM, Xiao Guangrong
<guangrong.xiao@...ux.intel.com> wrote:
> It walks all MTRRs and gets all the memory cache type setting for the
> specified range also it checks if the range is fully covered by MTRRs
>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@...ux.intel.com>
> ---
> arch/x86/kvm/mtrr.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 183 insertions(+)
>
> diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
> index e59d138..35f86303 100644
> --- a/arch/x86/kvm/mtrr.c
> +++ b/arch/x86/kvm/mtrr.c
> @@ -395,6 +395,189 @@ void kvm_vcpu_mtrr_init(struct kvm_vcpu *vcpu)
> INIT_LIST_HEAD(&vcpu->arch.mtrr_state.head);
> }
>
> +struct mtrr_looker {
> + /* input fields. */
> + struct kvm_mtrr *mtrr_state;
> + u64 start;
> + u64 end;
> +
> + /* output fields. */
> + int mem_type;
> + /* [start, end) is fully covered in MTRRs? */
s/fully/not fully/ ?
> + bool partial_map;
> +
> + /* private fields. */
> + union {
> + /* used for fixed MTRRs. */
> + struct {
> + int index;
> + int seg;
> + };
> +
> + /* used for var MTRRs. */
> + struct {
> + struct kvm_mtrr_range *range;
> + /* max address has been covered in var MTRRs. */
> + u64 start_max;
> + };
> + };
> +
> + bool fixed;
> +};
> +
> +static void mtrr_lookup_init(struct mtrr_looker *looker,
> + struct kvm_mtrr *mtrr_state, u64 start, u64 end)
> +{
> + looker->mtrr_state = mtrr_state;
> + looker->start = start;
> + looker->end = end;
> +}
> +
> +static u64 fixed_mtrr_range_end_addr(int seg, int index)
> +{
> + struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
> +
> + return mtrr_seg->start + mtrr_seg->range_size * index;
Should be (index + 1)?
> +}
> +
> +static bool mtrr_lookup_fixed_start(struct mtrr_looker *looker)
> +{
> + int seg, index;
> +
> + if (!looker->mtrr_state->fixed_mtrr_enabled)
> + return false;
> +
> + seg = fixed_mtrr_addr_to_seg(looker->start);
> + if (seg < 0)
> + return false;
> +
> + looker->fixed = true;
> + index = fixed_mtrr_addr_seg_to_range_index(looker->start, seg);
> + looker->index = index;
> + looker->seg = seg;
> + looker->mem_type = looker->mtrr_state->fixed_ranges[index];
> + looker->start = fixed_mtrr_range_end_addr(seg, index);
> + return true;
> +}
> +
> +static bool match_var_range(struct mtrr_looker *looker,
> + struct kvm_mtrr_range *range)
> +{
> + u64 start, end;
> +
> + var_mtrr_range(range, &start, &end);
> + if (!(start >= looker->end || end <= looker->start)) {
> + looker->range = range;
> + looker->mem_type = range->base & 0xff;
> +
> + /*
> + * the function is called when we do kvm_mtrr.head walking
> + * that means range has the minimum base address interleaves
> + * with [looker->start_max, looker->end).
> + */
I'm having trouble understanding this comment. I think this is what you
are trying to say:
this function is called when we do kvm_mtrr.head walking. range has the
minimum base address which interleaves [looker->start_max, looker->end).
Let me know if I parsed it wrong.
> + looker->partial_map |= looker->start_max < start;
> +
> + /* update the max address has been covered. */
> + looker->start_max = max(looker->start_max, end);
> + return true;
> + }
> +
> + return false;
> +}
> +
> +static void mtrr_lookup_var_start(struct mtrr_looker *looker)
> +{
> + struct kvm_mtrr *mtrr_state = looker->mtrr_state;
> + struct kvm_mtrr_range *range;
> +
> + looker->fixed = false;
> + looker->partial_map = false;
> + looker->start_max = looker->start;
> + looker->mem_type = -1;
> +
> + list_for_each_entry(range, &mtrr_state->head, node)
> + if (match_var_range(looker, range))
> + return;
> +
> + looker->partial_map = true;
> +}
> +
> +static void mtrr_lookup_fixed_next(struct mtrr_looker *looker)
> +{
> + struct fixed_mtrr_segment *eseg = &fixed_seg_table[looker->seg];
> + struct kvm_mtrr *mtrr_state = looker->mtrr_state;
> + u64 end;
> +
> + if (looker->start >= looker->end) {
> + looker->mem_type = -1;
> + looker->partial_map = false;
> + return;
> + }
> +
> + WARN_ON(!looker->fixed);
> +
> + looker->index++;
> + end = fixed_mtrr_range_end_addr(looker->seg, looker->index);
> +
> + /* switch to next segment. */
> + if (end >= eseg->end) {
> + looker->seg++;
> + looker->index = 0;
> +
> + /* have looked up for all fixed MTRRs. */
> + if (looker->seg >= ARRAY_SIZE(fixed_seg_table))
> + return mtrr_lookup_var_start(looker);
> +
> + end = fixed_mtrr_range_end_addr(looker->seg, looker->index);
> + }
> +
> + looker->mem_type = mtrr_state->fixed_ranges[looker->index];
> + looker->start = end;
> +}
> +
> +static void mtrr_lookup_var_next(struct mtrr_looker *looker)
> +{
> + struct kvm_mtrr *mtrr_state = looker->mtrr_state;
> +
> + WARN_ON(looker->fixed);
> +
> + looker->mem_type = -1;
> +
> + list_for_each_entry_continue(looker->range, &mtrr_state->head, node)
> + if (match_var_range(looker, looker->range))
> + return;
> +
> + looker->partial_map |= looker->start_max < looker->end;
> +}
> +
> +static void mtrr_lookup_start(struct mtrr_looker *looker)
> +{
> + looker->mem_type = -1;
> +
> + if (!looker->mtrr_state->mtrr_enabled) {
> + looker->partial_map = true;
> + return;
> + }
> +
> + if (!mtrr_lookup_fixed_start(looker))
> + mtrr_lookup_var_start(looker);
> +}
> +
> +static void mtrr_lookup_next(struct mtrr_looker *looker)
> +{
> + WARN_ON(looker->mem_type == -1);
> +
> + if (looker->fixed)
> + mtrr_lookup_fixed_next(looker);
> + else
> + mtrr_lookup_var_next(looker);
> +}
> +
> +#define mtrr_for_each_mem_type(_looker_, _mtrr_, _gpa_start_, _gpa_end_) \
> + for (mtrr_lookup_init(_looker_, _mtrr_, _gpa_start_, _gpa_end_), \
> + mtrr_lookup_start(_looker_); (_looker_)->mem_type != -1; \
> + mtrr_lookup_next(_looker_))
> +
> u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
> {
> struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
> --
> 2.1.0
>
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