QEMU-Devel Archive on lore.kernel.org
 help / color / Atom feed
From: Richard Henderson <richard.henderson@linaro.org>
To: David Hildenbrand <david@redhat.com>, qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org
Subject: Re: [Qemu-devel] [PATCH 4/6] exec: Factor out cpu_watchpoint_address_matches
Date: Wed, 28 Aug 2019 14:28:32 -0700
Message-ID: <a699d74e-c257-0abb-7680-1bd2038f1c88@linaro.org> (raw)
In-Reply-To: <77c9af3e-4c18-a20f-137e-468d04583241@redhat.com>

On 8/26/19 1:41 AM, David Hildenbrand wrote:
>> -    /* Make accesses to pages with watchpoints go via the
>> -       watchpoint trap routines.  */
>> -    QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) {
>> -        if (cpu_watchpoint_address_matches(wp, vaddr, TARGET_PAGE_SIZE)) {
>> -            /* Avoid trapping reads of pages with a write breakpoint. */
>> -            if ((prot & PAGE_WRITE) || (wp->flags & BP_MEM_READ)) {
>> -                iotlb = PHYS_SECTION_WATCH + paddr;
>> -                *address |= TLB_MMIO;
>> -                break;
> In the old code, we were able to break once we found a hit ...
> 
>> -            }
>> -        }
>> +    /* Avoid trapping reads of pages with a write breakpoint. */
>> +    match = (prot & PAGE_READ ? BP_MEM_READ : 0)
>> +          | (prot & PAGE_WRITE ? BP_MEM_WRITE : 0);
>> +    flags = cpu_watchpoint_address_matches(cpu, vaddr, TARGET_PAGE_SIZE);
>> +    if (flags & match) {
> ... now you cannot break early anymore. Maybe pass in the match to
> cpu_watchpoint_address_matches() ?

Hmm, yes, perhaps.

OTOH, summing a bitmask is a very quick operation.  Depending on the total
number of watchpoints, of course...


r~


  reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-24 21:34 [Qemu-devel] [PATCH 0/6] exec: Cleanup watchpoints Richard Henderson
2019-08-24 21:34 ` [Qemu-devel] [PATCH 1/6] exec: Move user-only watchpoint stubs inline Richard Henderson
2019-08-26  7:45   ` David Hildenbrand
2019-08-24 21:34 ` [Qemu-devel] [PATCH 2/6] exec: Factor out core logic of check_watchpoint() Richard Henderson
2019-08-24 21:34 ` [Qemu-devel] [PATCH 3/6] cputlb: Fold TLB_RECHECK into TLB_INVALID_MASK Richard Henderson
2019-08-26  8:36   ` David Hildenbrand
2019-08-24 21:34 ` [Qemu-devel] [PATCH 4/6] exec: Factor out cpu_watchpoint_address_matches Richard Henderson
2019-08-26  8:41   ` David Hildenbrand
2019-08-28 21:28     ` Richard Henderson [this message]
2019-08-28 21:54       ` David Hildenbrand
2019-08-24 21:34 ` [Qemu-devel] [PATCH 5/6] cputlb: Handle watchpoints via TLB_WATCHPOINT Richard Henderson
2019-08-28 22:00   ` David Hildenbrand
2019-08-24 21:34 ` [Qemu-devel] [PATCH 6/6] tcg: Check for watchpoints in probe_write() Richard Henderson
2019-08-28 21:47 ` [Qemu-devel] [PATCH 0/6] exec: Cleanup watchpoints Richard Henderson

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=a699d74e-c257-0abb-7680-1bd2038f1c88@linaro.org \
    --to=richard.henderson@linaro.org \
    --cc=david@redhat.com \
    --cc=peter.maydell@linaro.org \
    --cc=qemu-devel@nongnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

QEMU-Devel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/qemu-devel/0 qemu-devel/git/0.git
	git clone --mirror https://lore.kernel.org/qemu-devel/1 qemu-devel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 qemu-devel qemu-devel/ https://lore.kernel.org/qemu-devel \
		qemu-devel@nongnu.org qemu-devel@archiver.kernel.org
	public-inbox-index qemu-devel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.nongnu.qemu-devel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox