From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, Sean Christopherson <seanjc@google.com>,
Mathias Krause <minipli@grsecurity.net>,
Andrew Jones <andrew.jones@linux.dev>
Subject: [kvm-unit-tests PATCH v3 09/20] x86/vmx: Swap GPRs after checking "launched" status
Date: Thu, 14 May 2026 14:04:49 -0700 [thread overview]
Message-ID: <20260514210500.1626871-10-seanjc@google.com> (raw)
In-Reply-To: <20260514210500.1626871-1-seanjc@google.com>
When context switching GPRs before VM-Enter, check if the VMCS has been
launched before loading guest GPRs to ensure the assembly sequence doesn't
consume a guest GPR. The code currently works because "launched" is a
global variable and can be read with RIP-relative addressing, but that
won't hold true when launched is tracked per-CPU (or per-VMCS).
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
x86/vmx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/x86/vmx.c b/x86/vmx.c
index 4cb8d66c..7da549d1 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -1734,8 +1734,8 @@ static noinline void vmx_enter_guest(struct vmentry_result *result)
asm volatile (
"mov %[HOST_RSP], %%rdi\n\t"
"vmwrite %%rsp, %%rdi\n\t"
- SWAP_GPRS
"cmpb $0, %[launched]\n\t"
+ SWAP_GPRS
"jne 1f\n\t"
"vmlaunch\n\t"
"jmp 2f\n\t"
--
2.54.0.563.g4f69b47b94-goog
next prev parent reply other threads:[~2026-05-14 21:05 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-14 21:04 [kvm-unit-tests PATCH v3 00/20] x86: Better backtraces for leaf functions Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 01/20] x86/vmx: Drop unused SYSENTER "support" in nested VMX infrastructure Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 02/20] x86/vmx: Drop unused guest_regs " Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 03/20] x86/svm: Sort (and swap) GPRs by their index, not alphabetically Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 04/20] x86: Dedup guest/host context switch of registers across SVM and VMX Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 05/20] x86/virt: Use macro shenanigans to get reg offsets when swapping guest/host regs Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 06/20] x86/virt: Track "guest regs" using per-CPU variable Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 07/20] x86/svm: Don't VMLOAD/VMSAVE "guest" state around VMRUN Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 08/20] x86/vmx: Use separate VMCSes for BSP vs. AP in INIT test Sean Christopherson
2026-05-14 21:04 ` Sean Christopherson [this message]
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 10/20] x86/vmx: Track VMCS "launched" state per-CPU Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 11/20] x86/vmx: Track "is this CPU in guest mode" per-CPU Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 12/20] x86/vmx: Communicate hypercalls via RAX, not a global field Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 13/20] x86/vmx: Initialize test stage in SIPI test *before* launching AP thread Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 14/20] x86/kvmclock: Replace spaces with tabs Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 15/20] x86/kvmclock: Skip kvmclock test when not running on KVM with CLOCKSOURCE2 Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 16/20] x86/vmx: Tag "struct vmx_msr_entry" as needing to be 16-byte aligned Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 17/20] x86/smp: Align the stack to a 16-byte boundary when invoking SMP function calls Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 18/20] x86/vmx: Write to KVM's WALL_CLOCK MSR via VM-Entry load list sync in SIPI test Sean Christopherson
2026-05-14 21:04 ` [kvm-unit-tests PATCH v3 19/20] x86: Better backtraces for leaf functions Sean Christopherson
2026-05-14 21:05 ` [kvm-unit-tests PATCH v3 20/20] x86: Prevent realmode test code instrumentation with nop-mcount Sean Christopherson
Reply instructions:
You may reply publicly 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=20260514210500.1626871-10-seanjc@google.com \
--to=seanjc@google.com \
--cc=andrew.jones@linux.dev \
--cc=kvm@vger.kernel.org \
--cc=minipli@grsecurity.net \
--cc=pbonzini@redhat.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox