From nobody Wed Sep 24 13:02:47 2025 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4cWxpc04tlz67pXN; Wed, 24 Sep 2025 13:02:48 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R12" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4cWxpb4ygwz3WVF; Wed, 24 Sep 2025 13:02:47 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1758718967; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=x9hcztIR17zFgXZjL7BNnhEfbKmoP+5hx4xDH1VAGMc=; b=bHIIjyMkrp5GnAWuAOhJ+OVoDqRyPQ0GHc/vaZPlWf8784eiCZhyJwJ3XkQDgGDWL8Q6yI XicI6tnJVKDXoEpgKhQOa85EtXjnwY7XWCEKj1ZWxDZu/n+3Y3nrfTbR3C7AoJ/UsGJSGF St9zXPCK9DjxuL3doJqI9u8XQQf7TDbYl03TDi4NtE2cnpZdsD5OaXfWK2GDb5m3G8g+4M PTWIYBF/hfPEfyEm7Q0KUXvzsOWJKjZcRhq1pFViSOJiQNh+XiJ+BOTwvnrEHBbwaoUkpa mqFZCZzrNN5/5M8PqS5vgpgWmDaUDm2lLsXNX4NriaUX38KwIqn6QLn7VsL1Xw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1758718967; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=x9hcztIR17zFgXZjL7BNnhEfbKmoP+5hx4xDH1VAGMc=; b=X4GsO9BEJVJ9fbzFfsTTYeR1TeEULSGxIcCIlDdLz1AezbNUKRUJmN83YXhwGCdY+7G1lg jNpAHLOv/0uiMemJ4KpkWevK1oIs38lAYY4QCVaLaCJwvokgmt6Cwr9e2GzI+JnZrIzWo5 vh0bachpVcvZ8W93ZRP1j1VYDp8eg9sYbSdmvki63E8zqGELtohwxb+v4HWjWd2OFvXTPn +HRXeCsKdDXbVSquE6+N2ZnmuZxxUrRD6IHSgyKdwY5vNAicrjAwg2CjrCUCbL26l/Bodh zv9kJgmqqSaNg43C2JrKwgMlUV9rWwbovfueD70G6VCP8jXtCjnAHwWN/14l6g== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1758718967; a=rsa-sha256; cv=none; b=j/wptdkebQpD8oPWvqA0KEc9+70mJhEUw8JnJJfpP4hZ61bSi/edlaZo+wYrcs/41OVxmo 2UjZTjdKdiwCAeauJQwUJGcLX4bCSuT3Q8/4ReMFv/gf84Oh396zphyhtEw3NBLGfQzeOq +T6gsSAXRkEmqepUyoGaBnAu6nVRXbOqWTd2phkW2god3gk8gqWK+5eOjeTPVPd1QqRQot r7t+A6CRVgVKZUkpGmLUrx/8iO1Ak2KsKrzBBFmmm5Igu7I9+n/c6N3WCmk6FMQklbIhCc e7Hq0tV1rd10o0ITV+4pIzwBMFn2sUNxD0QERqvHdLqbk7Rb2KADY+3qMREOOg== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4cWxpb4Y8dzYvL; Wed, 24 Sep 2025 13:02:47 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 58OD2lsl034440; Wed, 24 Sep 2025 13:02:47 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 58OD2lKo034437; Wed, 24 Sep 2025 13:02:47 GMT (envelope-from git) Date: Wed, 24 Sep 2025 13:02:47 GMT Message-Id: <202509241302.58OD2lKo034437@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Konstantin Belousov Subject: git: a31969687545 - main - amd64: add wrmsr_early_safe(9) List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: kib X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: a319696875451229f492b6c15e58a0ac54dbcda1 Auto-Submitted: auto-generated The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=a319696875451229f492b6c15e58a0ac54dbcda1 commit a319696875451229f492b6c15e58a0ac54dbcda1 Author: Konstantin Belousov AuthorDate: 2025-09-18 21:55:19 +0000 Commit: Konstantin Belousov CommitDate: 2025-09-24 13:02:27 +0000 amd64: add wrmsr_early_safe(9) The variant of wrmsr_safe(9) that might work before IDT and curpcb are initialized. Assumes BSP, and that all APs are parked. Before calling wrmsr_early_safe(), the wrmsr_early_safe_start() should be called, afterward wrmsr_early_safe_end() restores the bootenv IDT. Reviewed by: markj Tested by: glebius Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D52607 --- sys/amd64/amd64/machdep.c | 33 +++++++++++++++++++++++++++++++++ sys/amd64/amd64/support.S | 16 ++++++++++++++++ sys/amd64/include/md_var.h | 4 ++++ 3 files changed, 53 insertions(+) diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c index 9ff60439d1ec..2fce1a7e64b6 100644 --- a/sys/amd64/amd64/machdep.c +++ b/sys/amd64/amd64/machdep.c @@ -1822,6 +1822,39 @@ clear_pcb_flags(struct pcb *pcb, const u_int flags) : "cc", "memory"); } +extern const char wrmsr_early_safe_gp_handler[]; +static struct region_descriptor wrmsr_early_safe_orig_efi_idt; + +void +wrmsr_early_safe_start(void) +{ + struct region_descriptor efi_idt; + struct gate_descriptor *gpf_descr; + + sidt(&wrmsr_early_safe_orig_efi_idt); + efi_idt.rd_limit = 32 * sizeof(idt0[0]); + efi_idt.rd_base = (uintptr_t)idt0; + lidt(&efi_idt); + + gpf_descr = &idt0[IDT_GP]; + gpf_descr->gd_looffset = (uintptr_t)wrmsr_early_safe_gp_handler; + gpf_descr->gd_hioffset = (uintptr_t)wrmsr_early_safe_gp_handler >> 16; + gpf_descr->gd_selector = rcs(); + gpf_descr->gd_type = SDT_SYSTGT; + gpf_descr->gd_p = 1; +} + +void +wrmsr_early_safe_end(void) +{ + struct gate_descriptor *gpf_descr; + + lidt(&wrmsr_early_safe_orig_efi_idt); + + gpf_descr = &idt0[IDT_GP]; + memset(gpf_descr, 0, sizeof(*gpf_descr)); +} + #ifdef KDB /* diff --git a/sys/amd64/amd64/support.S b/sys/amd64/amd64/support.S index 870cd255abb7..27694a95653c 100644 --- a/sys/amd64/amd64/support.S +++ b/sys/amd64/amd64/support.S @@ -1565,6 +1565,22 @@ msr_onfault: POP_FRAME_POINTER ret +ENTRY(wrmsr_early_safe) + movl %edi,%ecx + movl %esi,%eax + sarq $32,%rsi + movl %esi,%edx + wrmsr + xorl %eax,%eax +wrmsr_early_faulted: + ret + +ENTRY(wrmsr_early_safe_gp_handler) + addq $8,%rsp + movl $EFAULT,%eax + movq $wrmsr_early_faulted,(%rsp) + iretq + /* * void pmap_pti_pcid_invalidate(uint64_t ucr3, uint64_t kcr3); * Invalidates address space addressed by ucr3, then returns to kcr3. diff --git a/sys/amd64/include/md_var.h b/sys/amd64/include/md_var.h index b6ddc6eaaebe..b6d8c469cdf6 100644 --- a/sys/amd64/include/md_var.h +++ b/sys/amd64/include/md_var.h @@ -99,6 +99,10 @@ void get_fpcontext(struct thread *td, struct __mcontext *mcp, int set_fpcontext(struct thread *td, struct __mcontext *mcp, char *xfpustate, size_t xfpustate_len); +void wrmsr_early_safe_start(void); +void wrmsr_early_safe_end(void); +int wrmsr_early_safe(u_int msr, uint64_t data); + #endif /* !_MACHINE_MD_VAR_H_ */ #endif /* __i386__ */